Category 6™

Remembering a Crazy Flight Through Cat 5 Hurricane Gilbert, 25 Years Later

By: JeffMasters, 5:57 PM GMT on December 27, 2013

The year 2013 marked the 25th anniversary of 1988's Hurricane Gilbert--the most intense Atlantic hurricane ever measured up until that point, with a central pressure of 888 mb--a record has since been surpassed only by 2005's Hurricane Wilma. I was on the historic flight that caught Gilbert at its peak intensity, and below is my story of that flight, published here for the first time.

Jeff Masters

I awake early on September 13, 1988, not suspecting that I will be an eyewitness to meteorological history. I look out the window at the telltale bands of high cirrus clouds that curve across the Miami sky--far-flung outflow clouds streaming away from massive Hurricane Gilbert, centered over 500 miles to the southwest. Wow. This storm is huge. I turn on the news. The reports coming out of the Caribbean are shocking, heart-wrenching. Gilbert has ripped through Jamaica as a destructive Category 3 hurricane, delivering a crippling blow. At least 45 people are dead, and the island's infrastructure is devastated. Damage will be later estimated at $6.5 billion, making it Jamaica's costliest disaster of all-time. And the hurricane isn't done--Gilbert is now in the Western Caribbean, home of the Atlantic's deepest and warmest waters--rocket fuel for a Cape Verdes hurricane.

Figure 1. Hurricane Gilbert at peak intensity on September 13, 1988. Gilbert peaked at 175 mph winds and a central pressure of 888 mb.

Pre-Flight Briefing
I am the flight director for today's 11:30 am hurricane hunter mission on NOAA's N43RF hurricane research aircraft, affectionately named "Miss Piggy". On my way to Miami International Airport, I stop at the National Hurricane Center in Coral Gables to get a pre-flight weather briefing. Fittingly, the briefing comes from Gilbert Clark, the senior hurricane specialist on duty. Gil is the longest-serving and most knowledgeable hurricane forecaster working at NHC, and it is only fitting that his namesake storm will get its name retired the same year that he is retiring. Amidst the media zoo at NHC, Gil briefs me that the 8 am center fix from the Air Force reconnaissance aircraft in Gilbert shows Category 4 winds of 145 mph, and a central pressure of 934 mb. "The bottom's dropping out of this thing," he tells me, "and you just might be looking at a Cat 5 by the time you get there." I gulp down a bit of nervousness as I look at the imposing spiral of Gilbert's clouds, sprawled out over the entire Western Caribbean. The strongest hurricane I had flown through in two prior years with the Hurricane Hunters was a Category 3--1987's Hurricane Emily. After repeated penetrations into the eyewall of Emily, where the G-forces steadily rose until they hit three times the force of gravity, we finally had to abort the mission when a dangerous aerodynamic flutter developed in the wings. Hurricane Gilbert is far larger and more powerful than Emily was. Am I in for an even more dangerous ride?

Figure 2. An island of calm in a sea of chaos: NHC director Bob Sheets tries to get work done during the media zoo at NHC on September 14, 1988. Image credit: Jeff Masters.

Pre-Flight Preparations
I arrive at NOAA's Office of Aircraft Operations at Miami International Airport for pre-flight preparations. The energy at the office is electric. A film crew from the PBS show, "NOVA" is here. CNN is here, as are camera crews and reporters from half-a-dozen other media outlets. Three graduate students performing hurricane research for Dr. Bill Gray have just flown in this morning from Colorado to go on the flight. There isn't room for all of them. In the end, the grad students, the PBS NOVA crew, and the CNN crew get to go, but some of the media get left behind. "We've got plenty of media on board, and we'll do more good for the future of hurricane science by have these grad students go on the flight," my boss, Jim McFadden argues. Twenty-one people wind up on the flight, three more than the maximum we usually allow. The flight engineers are concerned about the aircraft's weight and balance, with such a large passenger list, but in the end they give the thumbs up to go, and we are on our way south towards the great storm.

Figure 3. Track of Hurricane Gilbert.

As we fly south over the Miami Beach, I look down on angry, white-capped waters. Here, 500 miles away from the eye, gale-force winds blow--an astoundingly large radius of strong winds for a hurricane. We chop through our first outer spiral band over the Florida Keys, and place a call to Cuba's Air Traffic Control center to get clearance to fly over the island. In those days, the Cuban government sometimes did not allow us to fly over the island, but for this storm, they give us immediate clearance. By the time we cross over Cuba 45 minutes later, we are plunging in and out of big cumulonimbus clouds with light turbulence and heavy rain showers. As we reach the south side of Cuba, Gilbert's eye comes clearly into view on the lower fuselage radar. The eye is very tight, ten miles in diameter, surrounded by an imposing swirl of reds and yellows on the radar screen. Lead scientist Hugh Willoughby and I have a critical decision to make--do we play it safe and penetrate the eye at 10,000 feet, where turbulence should be lighter? Or should we go in at 5,000 feet, where we will collect better data, but possibly risk hitting extreme turbulence? With the experience of last year's risky flight into Hurricane Emily fresh in my mind, I lobby for 10,000 feet, and Hugh goes along with this plan.

"Set Condition One!" crackles the voice of aircraft commander Dave Turner, as we begin our descent from our ferry altitude of 15,000 feet to our penetration altitude of 10,000 feet. I check the security of my heavy duty seat belt and shoulder harness, stow away my flight bag and clipboard, and prepare to meet the worst Gilbert has to offer. My heart beats faster, and an inner voice questions the wisdom of challenging one of nature's most fearsome storms in a mere mechanical creation. The formidable wall of dark clouds of Gilbert's eyewall lies just ahead. Darkness falls. The big plane lurches as turbulent winds grip us. Rain hammers down on the fuselage and streaks the windows. Flight-level winds jump from 90 mph to 115 mph. I watch the winds and radar carefully, and issue a request to Dave Turner for a slight course correction to keep us headed towards the eye. One minute in, two minutes to go. No significant turbulence yet. The eye, a remarkably small oasis of blue in a sea of angry reds and oranges on the radar, beckons. Two minutes in. The clouds grow thicker. The tip of the bouncing wing is hard to see through torrential rain, and the winds increase to 160 mph. A rough jolt hits us, as a 10 mph updraft gives way to a 3 mph downdraft in four short seconds. The plane skids forwards into a far more powerful updraft, which steadily increases to 10 mph, then 20 mph, and finally 35 mph. For a full minute this amazingly smooth updraft carries us higher into Gilbert's eyewall, even as the flight level winds crank up to a furious 185 mph. Category Five! The sky suddenly brightens as the updraft ejects us into the fearsome eye of monstrous Hurricane Gilbert.

Figure 4. Eye of Hurricane Gilbert taken from 10,000 feet from NOAA hurricane hunter aircraft N43RF at 5pm EDT September 13, 1988, when it was at peak strength as a Category 5 hurricane with a central pressure of 888 mb and 185 mph winds. Photo by Jeff Masters.

The Eye
The eye is awesome, supernatural, intense. We are at the edge of a stadium of majestic, towering cumulonimbus clouds that rise up high above us to a small circle of blue sky. The sun lights up a brilliant ring of whiteness along the top of the clouds. Beneath us is a white-capped ocean filled with chaotic, colliding waves up to 50 feet tall. Beneath the ragged bottom edge of the eyewall clouds, Gilbert's 175 mph surface winds whip the ocean surface into a greenish-white blur. I have little time to take in the spectacle, though, as I track the winds to make sure we penetrate to the exact center of the eye. I order one minor course correction, and then we have it--the winds drop to 4 mph, and we see a calm spot on the ocean below. "Let's mark it there!" I say. "Central pressure, 903 millibars." I pull out my VORTEX message form, and begin coding in the readings for transmission to the National Hurricane Center over our HF radio link. Within a minute, I have to stop, as we have arrived at the opposite west end of the eye, and a new eyewall penetration begins.

Figure 5. PBS's NOVA series videographer captures an image of Hurricane Gilbert from NOAA hurricane hunter aircraft N43RF on September 13, 1988. Image credit: Jeff Masters.

Rough Penetration
This time, the ride is rougher. Though the horizontal winds are weaker--165 mph--we hit a powerful 30 mph downdraft that leaves us nearly weightless at zero Gs. Commander Turner fights off the downdraft, keeping us at 10,000 feet. We pop out of the eyewall on Gilbert's west side, and begin a long trek to the south of the storm to do another penetration of the eye from south to north. I finish filling out my VORTEX report, unbuckle myself, and head back to the radio station to hand the report to our radio operator for transmission to NHC. The NOVA and CNN film crews are happy, busily taking footage of the crew at work. The scientists from NOAA's Hurricane Research Division are excitedly poring over the data we've collected. There's only been one storm stronger than this that they've flown into, Hurricane Allen of 1980. In another hour, that will no longer be true. The excitement we feel at being a part of meteorological history, though, is tempered by the somber realization that this storm is headed right for the Mexican resort areas of Cozumel and Cancun, which will undoubtedly suffer a catastrophic blow.

Figure 6. The VORTEX message I filed after penetrating through Hurricane Gilbert on September 13, 1988 and finding the lowest pressure ever measured in an Atlantic hurricane. A surface pressure reading was actually not filed at the time, since NHC told the crew that the pressures they were measuring were too low to be believable. The value shown here was added later after a research effort led by Hugh Willoughby determined 888 mb to be the actual pressure (myself and Chris Landsea, who was also on the flight, were co-authors on the paper documenting the new record.)

A New Record Low Pressure
We line up for our south-to-north penetration, and the crew takes their seats as the eyewall comes into sight. This time the winds are stronger--185 mph at flight level, gusting to 199 mph. We hit another huge updraft, 30 mph, but the ride is surprisingly smooth. As we pop into the eye, it is clear that Gilbert has intensified in the hour and half we've been way. The eye has shrunk to nine miles in diameter, and the central pressure has fallen to an astonishing 894 millibars--a spectacular nine millibar drop in just 90 minutes. Now, only the great Labor Day Hurricane of 1935 (892 mb central pressure) stands in the way of Hurricane Gilbert's run at all-time greatness. But there is controversy. Through an unfortunate oversight, we are not carrying any dropsondes, which we usually launch into the eye. Dropsondes fall to the surface on parachutes, and radio back the surface pressure. Instead, we have to estimate the surface pressure based on flight level measurements, which must be carefully calibrated. After sending in my VORTEX report with the 894 mb surface pressure from our second penetration, NHC radios back that they don't believe our surface pressures, and we are stop transmitting them for the VORTEX messages from our three final penetrations. The scientists and I protest this. Our instruments and our eyes show what NHC cannot see--we are witnessing meteorological history. Gilbert is clearly on its way to becoming the most intense hurricane of all-time.

After another long trek around the periphery of Gilbert, we punch through the eyewall an hour and a half later. This time, the eye is even more impressive, and the surface pressure has fallen another fifteen millibars, to an unbelievable 879 mb. (It turns out that NHC was right to question our pressure readings, as a later research effort led by Hugh Willoughby determined that 888 mb was the actual lowest pressure in Gilbert.) Our fourth penetration also measures 879 mb--Gilbert has finally finished intensifying. During our fifth and final penetration, we measure 883 mb, then head home. We arrive back in Miami nine hours after we took off. But, there is no rest for the weary: at 10 pm I am back at the frenzied media circus at NHC for a live remote interview with CNN's Larry King Live--my first-ever TV interview.

For more photos and eyewitness accounts of this amazing flight, check out the Gilbert Photo Gallery put together by Neal Dorst of NOAA's Hurricane Research Division. See also this remarkable video from Playa del Carmen, Mexico, as Gilbert made landfall on September 14, 1988, as a Category 5 hurricane.

My flight though Gilbert was one of two flights I did through a Category 5 hurricane. The story of my other Cat 5 flight, through Hurricane Hugo in 1989, is here. The story of that flight has been made into a 1-hour show that is scheduled to air on "Air Crash Investigation" (AKA "Mayday" outside the U.S.) on the National Geographic Channel in 2014, the 25th anniversary of Hurricane Hugo. Myself and six other veterans of the flight were interviewed for the show, which features a recreation of the near-fatal penetration into Hugo's eyewall, complete with actors playing the roles of the crew, and CGI sequences of stuff flying around the inside of the aircraft as we hit 5.7 Gs of acceleration.

Video 1. Nine-minute clip of the September 14, 1988 hurricane hunter mission into Hurricane Gilbert, as aired on the 1988 PBS NOVA show, "Hurricane."

I'll be back on January 6, 2014, with a new post. Have a Happy New Year, Everyone!

Jeff Masters


A Quiet But Deadly 2013 U.S. Fire Season

By: JeffMasters, 8:00 PM GMT on December 23, 2013

It was an unexpectedly quiet and deadly year for wildfires in the U.S. in 2013. The 4.2 million acres burned ranked as the 2nd lowest amount in the past ten years, according to the National Interagency Fire Center (NIFC.) The total number of wildfires was just over 43,100, which was well below the ten-year average of about 68,000 fires, and the lowest number since accurate record keeping began in the early 1980s. According to meteorologist Steve Bowen of Aon Benfield in an interview with USA Today, total wildfire economic damages during the year were approximately $700 million, or 46% below the 10-year average of $1.3 billion. However, 2013 was the third deadliest wildfire season for firefighters since records began in 1910, with 34 firefighters perishing.

The deadly Yarnell Hill, Arizona fire
On June 30, 2013, the third deadliest wildfire in U.S. history, Arizona's Yarnell Hill Fire, took the lives of 19 firefighters with the Prescott Fire Department's interagency Granite Mountain Hotshots. Close watch was on the weather during the fire, as temperatures hit 100° and winds gusted over 20 mph. However, a line of thunderstorms caused winds to increase and shift, gusting to over 40 mph, and changing direction from west-southwest to north-northeast. This rapid change in the winds caught the firefighters off guard, allowing the fire to quickly grow from 300 acres to 2,000 acres. It was this wind event with persistent hot temperatures and dry surface conditions that caused the erratic wildfire behavior and killed the 19 out of 20 Hotshots crew.

Video 1. The June 30, 2013 Yarnell Hill Fire in Arizona as seen from the air.

Figure 1. The Yarnell Hill Fire was the third deadliest wildfire in U.S. history. Image credit:

Didn't they say something about a record-breaking fire year? What happened?!
During the winter of 2012 and 2013, the nation was in the worst drought conditions since 2000 due to below normal snow pack across the West, according to the US Drought Monitor. The snowfall maps below show the percent of average snow pack over the Four Corners and Great Basin, respectively, measured April 1st, 2013 by the NRCS.

The chart below shows percent of drought conditions across the Contiguous U.S, with Exceptional Drought in dark red, Extreme Drought in red, Severe Drought in orange, Moderate Drought in tan, and Abnormally Dry in yellow.

As you can see from this chart, we started off 2013 at nearly the driest conditions across the U.S. since 2000, with nearly 80% of the country abnormally dry and over 6% in exceptional drought conditions. Due to the dry conditions, fire management agencies were expecting an exceptionally active fire season, since dry conditions in 2011 and 2012 caused historic fire years. (For example, the massive Wallow Fire in 2011 burned 538,000 acres in AZ and NM; the Whitewater-Baldy fire in 2012 was the largest single fire in New Mexico's history, at 297,845 acres; and the devastating 2012 Waldo Canyon Fire in Colorado was the most destructive fire in state history, with 346 homes burned.)

So what happened? During the summer of 2013, the Southwest benefited from a much wetter and more active monsoon season than in previous two years, which led to one of their wettest summers on record. For example, Colorado and the Four Corners reported record to near record wet conditions from July - November. Additionally, an active weather pattern across the Southeast U.S. brought near record wet conditions to Florida, Georgia, and the Carolinas. Traditionally, these two regions account for a large percentage of the annual acreage burned for the US. As you can see from the the NOAA statewide rank anomaly map below, for July - November, California was one of the few states that was dry during the peak part of fire season. This was a result of the quasi-stationary ridge of high pressure over the East Pacific for the majority of the year.

To a certain degree, luck was a significant component this year, as a major weather event like the 2008 Lighting Bust or the 2007 Santa Ana wind event simply did not occur in 2013. The Rim Fire, which burned into Yosemite National Park and ended up being the third largest wildfire in California history, was caused by a hunter's illegal campfire. The fire eventually consumed over a quarter million acres, and shows what the potential of the 2013 California wildfire season could have been if weather played a greater role.

Have a great Christmas, everyone, and I'll be back on Friday with a new post.

Jeff Masters, with major help from wunderground's fire weather expert, Kari Strenfel

Fire Climate Summaries

Haiyan's Storm Surge: A Detailed Look

By: JeffMasters, 8:49 PM GMT on December 19, 2013

The Philippines is a nation used to seeing devastating typhoons. Between 1984 and 2012, the Philippines saw seven tropical cyclones that killed at least 1,000 people. In all of these storms, it was destructive flooding due to heavy inland rains that was the main killer. This is in contrast to the Atlantic basin, where storm surge from the ocean has historically been the main killer. That's due, in part, to the fact that the Philippines gets hit more often by intense tropical cyclones than any place in the world, and this has influenced settlement patterns. The portion of the coast most prone to typhoon strikes--the east coast of Luzon Island--is not heavily populated, and does not have any major cities at low elevation that are prone to large storm surges. The islands of the Philippines farther to the south, like Leyte, Samar, and Mindanao, are hit far less often, since they are closer to the Equator, where typhoons have a tougher time getting spinning due to the lack of an extra boost from Earth's rotation. This relative lack of typhoon strikes has allowed more settlement on the east coast, and Tacloban (population 221,000) is the largest city on the Philippines' east coast. Tacloban also happens to be low-lying, with much of the city at less than ten feet elevation. It's position at the pointy end of a funnel-shaped bay makes its location particularly vulnerable to storm surge, since the topography acts to concentrate water at the apex of the funnel. The occurrence of a massive storm surge disaster in Tacloban was only a matter of time, and that time happened to be November 8, 2013, during Super Typhoon Haiyan.

Video 1. Nickson Gensis, Plan Philippines Community Development Worker, filmed from the top flood of a boarding house what is probably the most remarkable video of storm surge ever taken, during Super Typhoon Haiyan in Hernani, in Eastern Samar, Philippines. Australian tropical cyclone expert Bruce Harper had this to say about the remarkable "tsunami-like" storm surge observed at 46 seconds into the video:

This site at Hernani is quite exposed on the eastern coast of Samar, and has a fringing reef. My guess is that we are seeing the sudden exposure to deep water ocean swell waves that were triggered by the tide and sea level increase due to the storm surge. There is a critical water level where waves impacting on reefs can suddenly cause a massive increase in wave setup in the form of a tsunami-like effect such as we see in the video. A similar effect was reported at Basey, ten miles to the northeast of Tacloban across the San Juanico Strait, in this news report: "Edgar dela Cruz, 45, of Barangay Mercado, recounted to The STAR the sight of what looked like a tsunami. During the strange lull in the typhoon, he went out of his house. Jinamok Island was a kilometer across the sea from his village, he said. The sea receded about halfway to the island. 'There was a kind of low black cloud moving toward us,' Dela Cruz said. 'We heard a loud boom, like an explosion. And then we saw the giant waves--four giant waves--it was horrible.' Their house was destroyed. He said he and his family escaped with only the clothes on their backs." In this case, the reports suggest that northeast winds ahead of the center of Haiyan caused an initial “negative surge” effect in the shallow waters in this area, followed by the winds turning to E and SE as the center came closer. You can then develop quite a gradient in the water levels capable of producing this effect. The fast speed of the storm may also have contributed to this specific phenomenon. Andrew Kennedy, Associate Professor in Notre Dame's Department of Civil & Environmental Engineering & Earth Sciences wrote this email to me: "My student, Yao Zhang, has been doing some preliminary estimates of the waves and surge at Hernani, Eastern Samar, using a one-dimensional Boussinesq model. These show periodic surges and recessions very similar to those seen by Nickson Gensis in the video you referenced. Magnitudes are quite large--over 5 meters--which does not include any initial storm surge. I would not take all of the simulations as being perfectly accurate, since we do not have perfect bathymetry and incident waves. In any case, Yao has made a video of one of his model runs and it may be seen at" The middle plot is a zoomed-in version of the larger-scale version shown in the top panel.

Why wasn't Tacloban prepared for Haiyan's storm surge?
At this writing, at least 7900 people are dead or missing from Haiyan, making the typhoon the deadliest disaster in Philippine history. The vast majority of these deaths were due to storm surge. The Philippines have never had a storm surge disaster responsible for killing hundreds of people in living memory, and thus is was difficult to communicate the danger. As early as 36 hours before the storm, advisories from the Philippine meteorological agency, PAGASA, were predicting a storm surge of 15 feet for Tacloban. That should have been enough to trigger a mass evacuation of low-lying areas of Tacloban, yet this did not happen. As senior presidential aide Rene Alemendras said, "I was talking to the people of Tacloban...they said 'we were ready for the wind. We were not ready for the water."

Video 2. This animation by Deltares shows computed storm surge levels and wind vectors as Super Typhoon Haiyan makes landfall near Tacloban City, The Philippines. Surge levels were computed using Delft3D two days after landfall. The wind fields are based on Joint Typhoon Warning Center data, and generated a simulated storm surge of over 16.4 feet (5 meters) for Tacloban.

How high was Haiyan's storm surge?
According to storm surge expert Dr. Hal Needham, the record highest storm surge in modern history in East Asia was 24 feet (7.3-meters) in 1897 on Samar Island, Philippines--the same location where Haiyan initially hit. He estimated that Haiyan's surge was very close to that at the Tacloban Airport: 21.3 feet (6.5 meters). Storm chaser Josh Morgerman of rode out the storm in a hotel a mile northwest of the airport, where the surge may have been even higher, due to the shape of the coast. He stated in an email to me that "we determined our location to be at 26 ft (based on USGS data), and we flooded to a depth of about 4 ft, suggesting a whopping 30-ft surge. (Afterward, I had a geography expert research this, and he came up with the same value for our location—8 m or 26 ft.)" A storm surge of 21 - 30 feet hitting densely populated Tacloban, which did not fully evacuate low-lying areas, was bound to cause thousands of deaths.

A detailed look at Haiyan's storm surge
Hurricane scientist Margie Kieper, who wrote a remarkable analysis of Hurricane Katrina's storm surge for wunderground, also studied Haiyan's storm surge in detail. The rest of this post is her analysis.

You know the more I reflect on the surge damage from STY Haiyan the more I realize this is an enormously extensive surge. Even considerably far north of the eye along Eastern Samar's Pacific coast water came inland with enough height and velocity to destroy all coastal towns. And in the Gulf of Leyte, the surge damage along the coast was just as extensive and dramatic. Unfortunately, there seems to be only the one main coastal road ringing the island of Samar, to provide access to all these coastal communities.

Figure 1. Locations in the Philippines where a significant storm surge from Super Typhoon Haiyan was observed.

I just don't think I have ever seen anything on par with this. And this was a primarily rural area with small towns, not a developed coastline as with Katrina, Ike, etc. Haiyan's surge was most severe in Leyte, Samar, and Eastern Samar bordering the Gulf of Leyte, and the Pacific Coast of Eastern Samar (see map). Surge heights were on par with forecasts publicized by Philippines meteorological service, and may even have been a little higher than the forecasts. Their surge numbers were generated using the Japan Meteorological Agency (JMA) Storm Surge model using JMA forecast data and WXTide results. The model predicted 15 feet (4.5 meters) for Tacloban, and an estimate of about 21 feet has been suggested by Dr. Hal Needham on

The storm surges at Tacloban and across the bay at Basey have been well-documented in the news. But along the Leyte coast south of Tacloban, the communities of Palo, Tanauan, Tolosa, and Dulag also received significant surge. Coastal communities along the northern shore of the Gulf of Leyte, and the connecting road, which runs in many places right along the shore, were all also destroyed by surge. Here, also, bridges along the coastal road such as at Lawaan, were also destroyed. In Samar, Basey and Marabut were heavily damaged by surge.

Figure 2. Storm surge damage from Haiyan in Palo, near where the center of the eye passed. This location is just south of Tacolban on Leyte Island. Image credit:

Figure 3. Storm surge damage from Haiyan in Tolosa, just south of where the center of the eye passed. This location is south of Tacolban on Leyte Island. Image credit:

Figure 4. Storm surge damage from Haiyan in Hernani on Samar Island. Image credit:

Figure 5. Storm surge damage from Haiyan in Lawaan on Samar Island. Image credit:

Figure 6. Storm surge damage from Haiyan in Marabut on Samar Island. Image credit:

Figure 7. Storm surge damage from Haiyan on Victory Island, Samar. Image credit: Getty Images.

Eastern Samar Representative Ben Evardone, in an interview with Rappler, noted that eleven out of the 23 municipalities in Eastern Samar were devastated by the storm, plus the Borongan City and the island of Homohon: Lawaan, Balangiga, Giporlos, Quinapondan, Macarthur, Hernani, Balankayan, Maydolong, Salcedo, Mercedes, and Guiuan. After a helicopter survey, he told reporters, “There is no more Eastern Samar province. You cannot recognize it. The devastation was horrific."

One other location that had extremely high surge was Hernani, facing the Pacific Ocean north of Matarinao Bay, where the storm surge was described as being two stories high. Hernani and Balangkayan are described as "destroyed" by the surge, and photos from Rappler's Franz Lopez bear this out (the entire photo essay can be seen at ). The surge obliterated the "first two rows" of houses along the shore at Balangkayan and eroded the beachfront there.

North of Hernani, along the Pacific Coast of Eastern Samar, surge destroyed bridges at the capital Borongan and at General MacArthur. The governor of Eastern Samar was not familiar with the term "storm surge" and was quoted as saying, "Nobody expected the sea water to surge through the towns. Usually, typhoons here just bring rain. Those who live near rivers and rice fields, they’re the ones who are asked to evacuated. Those living near the shoreline, that’s unexpected." In other words, they were familiar with freshwater flooding issues from heavy rainfall, but not familiar with storm surge. A resident of Maydolong, north of Balangkayan, described the damage as similar to a nuclear bomb, an analogy commonly invoked to describe surge damage. These areas also received strong winds which resulted in flying debris in the air at the same time the surge was moving inland. South of Hernani, in Guiuan, homes right on the coastline or built on peninsulas little more than sandbars, known in the U.S. as being in the "velocity zone", were also obliterated by water.

Video 3. The storm surge in Tacloban, Philippines during the landfall of Super Typhoon Haiyan is captured at about the 3:30 - 4:20 mark in this video shot by ABSCBN News of the Philippines.

The 1912 typhoon that devastated Tacloban
Haiyan is not the first typhoon to devastate Tacloban. The Philippine Star reported on a November 26, 1912 typhoon that struck the city. The news story from the Washington Herald that they cite reads: "That 15,000 persons were probably killed and wounded in a typhoon...probably half the population of the two cities had been lost." A pressure trace from the city showed the pressure fell to an impressive 924 mb during the typhoon. However, weather maps of the event show that the eye of the typhoon may have passed just north of the city, preventing a massive storm surge from hitting. There were three New York Times articles about this typhoon, one reporting about 300 killed, and another reporting, "Despite the enormous damage in Tacloban, the capital of Leyte, the fatalities there were less than a dozen." Thanks go to hurricane scientist Sim Aberson of NOAA's Hurricane Research Division for this info.

Jeff Masters and Margie Kieper


Earth has its Warmest November in Recorded History

By: JeffMasters, 4:49 PM GMT on December 17, 2013

November 2013 was the globe's warmest November since records began in 1880, according to NOAA's National Climatic Data Center (NCDC) and NASA. The year-to-date period of January - November has been the 4th warmest such period on record. November 2013 global land temperatures were the 2nd warmest on record, and global ocean temperatures were the 3rd warmest on record. November 2013 was the 345th consecutive month with global temperatures warmer than the 20th century average. Global satellite-measured temperatures in November 2013 for the lowest 8 km of the atmosphere were 16th or 9th warmest in the 35-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH), respectively. Northern Hemisphere November snow cover was the 16th greatest in the 48-year record. Wunderground's weather historian, Christopher C. Burt, has a comprehensive post on the notable weather events of November 2013 in his November 2013 Global Weather Extremes Summary.

Figure 1. Departure of temperature from average for November 2013, the warmest November for the globe since record keeping began in 1880. Most of the world's land areas experienced warmer-than-average monthly temperatures, including much of Eurasia, coastal Africa, Central America, and central South America. Much of southern Russia, north west Kazakhstan, south India, and southern Madagascar were record warm. Meanwhile, northern Australia, parts of North America, and southwest Greenland were cooler than average. No regions of the globe were record cold. According to Roshydromet, Russia observed its warmest November since national records began in 1891. Image credit: National Climatic Data Center (NCDC) .

The four billion-dollar weather disasters of November 2013
Four new billion-dollar weather-related disasters hit the Earth during November 2013: Super Typhoon Haiyan ($5.8 billion), the November 17 tornado outbreak in the U.S. ($1.7 billion), flooding in Cambodia ($1 billion, the costliest disaster in Cambodian history), and the ongoing U.S. drought, which has been in progress all year, but with damages listed for the first time this year ($2.5 billion.) These four disasters bring the world-wide tally of billion-dollar weather disasters so far this year to 39, according to the November 2013 Catastrophe Report from insurance broker Aon Benfield. This is the second highest yearly total of billion-dollar weather disasters for the globe since accurate disaster records began in 2000. However, the total cost of weather-related disasters so far in 2013 is below the average for the past ten years, according to Senior Scientist Steve Bowen of Aon Benfield. The record highest number of billion-dollar weather disasters was 40, set in 2010. For comparison, during all of 2012, there were 27 billion-dollar weather disasters. The U.S. total through November 2013 is nine.

Disaster 1. Super Typhoon Haiyan hit the Central Philippines on November 8, 2013, as one of the strongest tropical cyclones in world history, with peak surface winds estimated at 195 mph by the Joint Typhoon Warning Center. Haiyan killed over 6,000 people and did at least $5.8 billion in damage, making it the costliest and 1st or 2nd deadliest disaster in Philippine history. In this image, we see a Filipino boy carrying bottled water amongst the damaged houses where a ship was washed ashore in Tacloban city, Leyte province, central Philippines on Sunday, Nov. 10, 2013. (AP Photo/Aaron Favila)

Disaster 2. The most expensive November tornado outbreak hit the U.S. on November 17, causing damage estimated at $1.6 billion. This image shows a view of part of Washington, Illinois from Mackenzie Street on Sunday, Nov. 17, 2013, after an EF-4 tornado tore through the area, one of three EF-4 tornadoes from the outbreak. (AP Photo/Alex Kareotes)

Disaster 3. Heavy monsoon rains caused the Mekong River in Cambodia to overflow its banks in October and November 2013, causing $1 billion in damage. According to the International Disaster Database, EM-DAT, this would make the disaster Cambodia's most expensive and 6th deadliest natural disaster in its history. In this photo, we see Cambodian children swimming in flood waters at a village in Kandal province on October 7, 2013. Photo credit: TANG CHHIN SOTHY/AFP/Getty Images)

Disaster 4. The on-going U.S. drought has cost at least $2.5 billion so far in 2013. In this image, we see that Lake Mead water levels from 1938 - 2013 in July have shown a precipitous drop since drought conditions gripped the Western U.S. in 2000. The Lake Mead photo was taken by wunderphotographer LAjoneson June 29, 2007, when the lake had a "bathtub ring" 109' tall. Water level data from The Bureau of Reclamation is overlaid.

Neutral El Niño conditions continue in the equatorial Pacific
For the 19th month in row, November 2013 featured neutral El Niño conditions in the equatorial Eastern Pacific. The December 5 El Niño discussion from NOAA's Climate Prediction Center notes that "While current forecast probabilities are still greatest for ENSO-neutral by mid-summer, there is an increasing chance for the development of El Niño. None of the El Niño models predict La Niña conditions by the summer of 2014, and 7 of 16 predict El Niño conditions. Temperatures in the equatorial Eastern Pacific need to be 0.5°C below average or cooler for three consecutive months for a La Niña episode to be declared; sea surface temperatures were 0.0°C from average as of December 16, and have been +0.1 to -0.4°C from average since April 1, 2013.

Arctic sea ice falls to 6th lowest November extent on record
Arctic sea ice extent during November was 6th lowest in the 35-year satellite record, and had the largest November extent since 2010, according to the National Snow and Ice Data Center (NSIDC).

Jeff Masters

Climate Summaries

A Spectacular Tropical Storm-Like Meso-Low Over Lake Superior

By: JeffMasters, 3:46 PM GMT on December 16, 2013

A small-scale "meso-low" formed in the cold Arctic air flowing over the relatively warm waters of Lake Superior on Sunday, and had a remarkably spectacular tropical storm-like appearance on radar and satellite imagery. As the meso-low moved south over Michigan's Upper Peninsula, it brought sustained winds of 20 - 25 mph and bands of moderate snow that dumped 4 - 7 inches of snow across the region. The snow was dry and fluffy, with a ration of 25:1 between the depth of the snow and depth of the equivalent melted water (a 10:1 ratio is more common in major snowstorms.) The winds in Marquette, Michigan increased from 10 mph to 23 mph with gusts to 32 mph as the meso-low moved over at 4 pm. In nearby Munising, the pressure increased from 1005 mb to 1015 mb in four hours after the low moved through. As documented in a 1984 paper by Dr. Greg Forbes, "Mesoscale Vorticies over the Great Lakes in Wintertime", these type of lows are not uncommon over the Great Lakes in wintertime, with an average of three appearing each winter. They arise in response to the difference in heating between the land and the lake when there is a strong contrast in temperature, and do not occur when the lakes are ice-covered.

Figure 1. From the NWS Marquette Facebook page: "In this image a meso-low can be seen (shown in the blue circle), which is a smaller scale low pressure system that commonly forms on the Great Lake during the winter time. This is primarily what has been responsible for the strong gusty winds and heavy snow bands that have been pushing into areas along the Marquette and Alger county shorelines. The system even has sort of an awesome eye near the center of rotation. This image was take around 1:30 pm EST."

Figure 2. Radar image of the meso-low after it moved ashore over Michigan's Upper Peninsula.

Figure 3. The pressure trace (2nd graph) from Munising, Michigan showed a sharp rise in pressure from 1005 mb to 1015 mb in four hours after a meso-low moved through.

A radar loop of the meso-low as it approached land. Thanks go to wunderground member StAugustineFL for saving this radar loop.

The University of Wisconsin CIMSS Satellite Blog has an in-depth discussion of the meso-low.

Jeff Masters

Winter Weather

Taming Hurricanes With Wind Turbines

By: JeffMasters, 7:35 PM GMT on December 13, 2013

How can one significantly reduce the winds of nature’s most destructive storms, and at the same time provide up to half of the world’s electric power? The answer, according to Dr. Mark Jacobson of Stanford’s Civil and Environmental Engineering department, is to install massive arrays of tens of thousands of offshore wind turbines, which can extract wind energy from hurricanes and dramatically reduce their winds and storm surges. I’m in San Francisco this week for the annual meeting of the American Geophysical Union (AGU), the world’s largest climate science conference, where Dr. Jacobson presented a talk titled, “Taming hurricanes with arrays of offshore wind turbines that simultaneously reduce global warming and air pollution and provide normal electric power.” Using a 3-D global atmospheric computer model with finer-scale meshes zoomed in along the U.S. coast, he ran simulations of Hurricane Katrina and Hurricane Sandy, and studied how an array of 70,000 wind turbines that generate 300 Gigawatts of power placed along the coast might impact these storms. The simulations showed that as the outer winds of these hurricanes moved over the wind turbines, they extracted enough energy from the storms to reduce the winds by 50%, and increase the central pressure by 16 mb. A decrease in the storm surge of 6 - 72% occurred as a result.

Figure 1. The wind speeds at 15 meters above the surface as simulated at 10 am EDT August 29, 2005 during Hurricane Katrina. Left: Katrina’s winds without an off-shore wind turbine array of 70,000 units present (7.58-MW Enercon E-126 turbines spaced every 0.45 km2 within 100 km of the coast.) Right: Hurricane Katrina after passing through the simulated array. The wind turbines extracted a huge amount of energy from the hurricane, significantly reducing its winds. Image credit: Mark Jacobson and Cristina Archer, “Taming Hurricanes With Arrays of Offshore Wind Turbines”, presentation made to the Willet Kempton Wind Energy Symposium University of Delaware February 27, 2013.

Vulnerability of wind turbines to hurricane winds
The wind turbines used in the study shut down when winds hit 76 mph, and are destroyed at wind speeds of 112 mph. The eyewall winds of Katrina did destroy a number of turbines in the simulation. Even so, the cost of the lost turbines in such a case would likely be made up for by the reduced damage of the hurricane’s winds and storm surge at the coast due to the presence of the wind turbine array. Note that a 2012 paper by Rose et al. that got a lot of media attention, “Quantifying the hurricane risk to offshore wind turbines“, significantly overestimated the risks of wind turbines being destroyed by a hurricane, as pointed out by NOAA hurricane scientist Dr. Mark Powell, and as conceded by the authors of the study. It is reasonable to build large offshore arrays of wind turbines in hurricane-prone regions, provided some extra engineering effort is put into the design of these turbines. A talk presented at AGU yesterday by Jay Apt and Stephen Rose of Carnegie Mellon University, “Quantifying the hurricane risk to offshore wind power,” recommended that offshore wind turbines install backup power systems in order to orient the blades correctly to reduce extreme wind loads during hurricane conditions.

More research needs to be done on how large wind turbine arrays might affect the weather. These turbines could potentially cause significant changes to precipitation patterns along the coast. As I blogged about in 2012, in the Southeast U.S., tropical cyclones provide 15 - 20% of the annual precipitation, and 20% - 50% of all droughts between 1960 - 2009 were busted by a landfalling tropical storm or hurricane. If wind turbine arrays reduce the intensity of tropical storms making landfall, it makes sense that the amount of rain they dump will also decline. Droughts are often more damaging than hurricanes, and it may be necessary to shut down a large array of coastal wind turbines in a situation where a tropical storm or hurricane with drought-busting rains is headed for a drought region. Who should make this decision? How strong of a storm should we let hit? There are many tough questions to answer.

Figure 2. Wind turbine damage on Miyakojima Island, Japan after Typhoon Maemi struck on September 11, 2003. Image credit: Takahara, et al., 2004, “Damages of wind turbine on Miyakojima Island by Typhoon Maemi in 2003.”

Wind to power the world?
Dr. Jacobson is a big booster of wind power. A 2012 paper that he published along with co-author Christina Archer in Proceedings of the National Academy of Sciences (PNAS) found that there is enough wind to exceed the total world energy demand by several times, even after accounting for reductions in wind speed caused by the wind turbines. Their model showed that 4 million turbines, each operating at a height of 100 meters and producing 5 megawatts, could supply 7.5 terawatts of power—more than half the world's all-purpose power demand—without significant negative effects on the climate. "To get there, however, we have a long way to go. Today, we have installed a little over 1 percent of the wind power needed," Jacobson said, in a Stanford press release. Half of the 4 million turbines would be situated over water, and the other 2 million would require a little more than 0.5% percent of Earth's land surface—about half the area of the state of Alaska. However, virtually none of this area would be used solely for wind, but could serve dual purposes such as open space, farmland, ranchland or wildlife preserve.

Have a great weekend, everyone, and I’ll be back Monday with a new post.

Jeff Masters


Holiday Shopping Guide for the Weather Enthusiast

By: JeffMasters, 6:18 PM GMT on December 11, 2013

What’s the hottest gift of the year for the weather enthusiast? It’s the 2014 Climate Models Calendar, featuring the world’s hottest climate scientists posing in front of provocative backgrounds. I’m in San Francisco this week for the annual meeting of the American Geophysical Union (AGU), the world’s largest climate science conference. Over five thousand of the world’s top climate scientists are here, giving a staggering 10,000 talks and poster presentations. One of the poster presentations yesterday was for the Climate Models Calendar, a crowd-funded project that raised $10,000 to make this humorous calendar of “climate models”. The calendar includes information about the climate models’ research, favorite datasets, and has memorable dates in weather and climate history.  You can pick up a copy of the the Climate Models Calendar for your favorite weather and climate science enthusiast at; it’s $20.

Figure 1. Front cover of the 2014 Climate Models Calendar.

Buy a Personal Weather Station!
Every serious weather enthusiast deserves a Personal Weather Station (PWS) in their backyard! Not only can you enjoy seeing what the weather is in your backyard, you can share the data with everyone else on the Internet by uploading to the Wunderground Personal Weather Station network, which boasts data from over 25,000 stations. You don’t need to have a computer on all the time to collect the data and send it to the Internet—a company called Ambient makes a weather bridge that will keep the data flowing to the Internet even when your computer is turned off. A full list of wunderground-compatible PWS models, software, and add-ons like the Ambient weather bridge is available from our Personal Weather Station page. I have had a Davis Vantage II Pro in my backyard for the past five years, and have been very happy with it, but Rainwise also makes an excellent PWS that is very easy to set up.

Holiday books for the climate science enthusiast
If your favorite climate science enthusiast hasn’t read “The Hockey Stick and the Climate Wars: Dispatches from the Front Lines”, by Michael E. Mann, now is the time to give him or her this must-read book. It’s out in paperback for the first time, and the new paperback edition includes a postscript from the author updating the story, and a new foreword from Bill Nye the Science Guy. My 2012 review of the book is here. The paperback version of “The Hockey Stick and the Climate Wars” is $19.95 from the Columbia University Press.

If your climate science enthusiast’s reading taste runs more towards fiction, there is a whole new genre of climate fiction called “cli-fi” that has emerged in recent years. The best book I’ve read in this genre so far is “Flight Behavior” by Barbara Kingsolver. Kingsolver's story concerns a young wife and mother on a failing farm in rural Tennessee who experiences something she cannot explain—the mass migration of monarch butterflies from Mexico to new overwintering grounds in Tennessee. Her discovery energizes various competing factions—religious leaders, climate scientists, environmentalists, politicians—trapping her in the center of the conflict and ultimately opening up her world. Given the huge crash in monarch butterfly numbers in 2013, this novel is particularly timely. “Flight Behavior” is $10.63 in paperback from Amazon. I’ve read two other works of “cli-fi” this year that I enjoyed. ”Year of the Bad Decision” by Charles Sobczak tells the story of a geoengineering project in the year 2043 gone horribly wrong. ”A Change in the Weather” by Raymond Welch is set in 2028, and focuses on an Orwellian U.S. society that comes about in response to severe climate change.

Follow this week’s talks at AGU via the Internet
You can watch live streaming and recorded talks at this week’s AGU meeting—nearly 100 sessions (almost 600 presentations in total)  will be available live and on demand. Register here, and be sure to use code AGU13 for free access. You can also browse thousands of poster presentations at the poster site.
I’ll have a new post by Friday at the latest.

Jeff Masters

Book and Movie Reviews

Brrrr! -135.8°F Measured at Earth's New Coldest Spot

By: JeffMasters, 4:23 PM GMT on December 10, 2013

I’m in San Francisco this week for the annual meeting of the American Geophysical Union (AGU), the world’s largest climate science conference. Over five thousand of the world’s top climate scientists are here, giving a staggering 10,000 talks and poster presentations. It’s total information overload, and I will only be able to offer this week but a small sampling of the incredible amount of science being presented here.

What is the coldest place in the world? It is a high ridge above 13,000 feet in Antarctica on the East Antarctic Plateau where temperatures in several hollows can dip below minus 135.8 degrees Fahrenheit (minus 92.2 degrees Celsius) on a clear winter night, announced polar scientist Ted Scambos of the National Snow and Ice Data Center, at a Monday press conference at the AGU conference. The official world cold record of minus 128.6 F (minus 89.2 C), set in 1983 at the Russian Vostok Research Station in East Antarctica will remain intact, though, since official records have to be measured by ground-based instruments. How cold is -135.8°F? That’s so cold that it would hurt to breathe, said Dr. Scambos in an AP interview. That’s also well below the -109°F temperature that dry ice (frozen carbon dioxide) begins to sublimate into gaseous carbon dioxide. But don’t get your hopes up that we can use the newly-found record cold spot to take CO2 out of the air and solve global warming—you need a temperature of -220°F (-140°C) to freeze CO2 out the air into dry ice “snow” at the concentrations that CO2 exists at in our atmosphere (about 398 ppm.) Still, it is an intriguing concept to build giant refrigerators in Antarctica to do just that—something that has been proposed by Purdue climate scientist Ernest Agee, in a research paper titled, CO2 Snow Deposition in Antarctica to Curtail Anthropogenic Global Warming, published earlier this year in the Journal of Applied Meteorology and Climatology .

Figure 1. With remote-sensing satellites, scientists have found the coldest places on Earth, just off a ridge in the East Antarctic Plateau. The coldest of the cold temperatures dropped to minus 135.8 F (minus 93.2 C)--several degrees colder than the previous record. Image Credit: Ted Scambos, National Snow and Ice Data Center.

Video 1. The coldest place on earth. Data from NASA-USGS Landsat 8 satellite, and NASA's MODIS sensor on the Aqua satellite. Image Credit:  NASA's Goddard Space Flight Center

Figure 2. In this spectacular photo from Antarctica taken by a NASA scientist on November 24, 2013, we see a lenticular cloud over a pressure ridge in the Antarctic sea ice. Lenticular clouds are a type of wave cloud. They usually form when a layer of air near the surface encounters a topographic barrier, gets pushed upward, and flows over it as a series of atmospheric gravity waves. Lenticular clouds form at the crest of the waves, where the air is coolest and water vapor is most likely to condense into cloud droplets. The bulging sea ice in the foreground is a pressure ridge, which formed when separate ice floes collided and piled up on each other. Image credit: NASA Earth Observatory.

Follow this week’s talks at AGU via the Internet
You can watch live streaming and recorded talks at this week’s AGU meeting—nearly 100 sessions (almost 600 presentations in total)--will be available live and on demand. Register here, and be sure to use code AGU13 for free access. You can also browse thousands of poster presentations at the poster site.
Amusing story: Metallica Has Officially Rocked on Every Continent Following Antarctica Gig on Sunday

Jeff Masters

Climate Change Winter Weather

New Round of Snow and Ice for the U.S.; Extreme Warmth in Alaska

By: JeffMasters, 3:42 PM GMT on December 09, 2013

The calendar says we’re still a month and a half away from the peak of winter, but the winter weather gripping most of the U.S. is more typical of mid-January, as a significant outbreak of Arctic air continues to bring temperatures 10 - 30 degrees below normal to much of the nation. Following last Friday’s major winter storm that brought heavy snows and significant icing from Texas to Maine (“Cleon”), a new winter storm dubbed “Dion” followed a similar track on Sunday. The storm brought the first snow of winter to Washington D.C., New York City, and Philadelphia (the average date of the first measurable snow ranges from Dec. 14 in Baltimore to Dec. 18 in Philadelphia and Washington.) The 8.6” of snow that fell on Philadelphia surpassed the snowfall total for the entire 2012-2013 season (8.3”.) Snow and blowing snow hit four NFL games on Sunday—Lions at Eagles, Vikings at Ravens, Chiefs at Redskins, and Dolphins at Steelers—so obscuring the yard markers, that it was almost impossible for fans to tell exactly where the ball was at all four stadiums. The snow caused multiple traffic accidents that shut portions of I-95 in Philadelphia, and all planes were grounded at the airport during the afternoon. Farther west in Pennsylvania, heavy snow caused a 56-car pile up on the westbound lanes of the Pennsylvania Turnpike from Downingtown to Morgantown, after a motorist got out of his car after a minor accident and was hit and killed. One other person was injured. I-78 in Pennsylvania was also closed by traffic accidents on Sunday. More that 1/4” of ice accumulated due to freezing rains in portions of Kentucky, Tennessee, Virginia, Maryland, and West Virginia.

Figure 1. Pregame festivities at Sunday’s Lions-Eagles game in Philadelphia looked like a scene out of “Frozen.” Image credit: CNBC's Jim Cramer (@jimcramer)

Severe cold wave due to an unusually extreme jet stream kink
As we’ve so many times over the past few years, the jet stream is stuck in an unusually wavy configuration that is bringing remarkable hot and cold weather extremes to the entire continent. A sharp trough of low pressure over the center of North America is allowing frigid Arctic air to barrel unusually far south, setting hundreds of daily records over the past few days. Temperatures in Northern Montana were as much as 50 degrees below normal, and in portions of Oregon, the cold blast brought the coldest temperatures since 1972. One station even set an all-time cold record: Lakeview, Oregon hit -27° on December 8, breaking the old all-time cold record of -24° set on Jan. 15, 1888. Temperature records there began in 1884.

Unusually extreme ridges of high pressure set up over Alaska and the Southeast United States to compensate for the big dip in the jet stream over the center of North America. One ridge of high pressure pushed to the north of Alaska and over the Arctic Ocean, allowing warm Pacific air to bring rain and temperatures in the upper 30s to Alaska’s North Slope on Sunday—an unprecedented occurrence in December. Keep in mind that this is an area that has been in perpetual 24-hour darkness for several weeks. According to wunderground’s weather historian Christopher C. Burt, it appears that Sunday’s 39° at Deadhorse (Prudhoe Bay) is the warmest December temperature ever measured at any site on the Alaskan Arctic Ocean shoreline region. Weather records for Alaska’s North Slope go back as far as 1921 at Point Barrow. A very sharp ridge of high pressure also set up over the Southeast U.S.—Tallahasse, Florida hit 84° on Saturday, matching their highest temperature ever recorded in the month of December.

Figure 2. Jet stream winds over North America on Sunday, December 8, showed a sharp trough of low pressure over the center of the continent, allowing cold Arctic air to spill southwards into the U.S. Sharp ridges of high pressure were over Alaska and the Southeast U.S.

Jeff Masters

Winter Weather Extreme Weather

Cold, Ice, and Snow Assault U.S.; Windstorm Xaver Kills 6 in Europe

By: JeffMasters, 3:51 PM GMT on December 06, 2013

A frigid winter cold blast has most of the U.S. in an icy grip, as cold air plunging southwards from Canada will bring temperatures 10 - 40 degrees below average to more than 80% of the contiguous U.S. on Friday, Saturday, and Sunday. The most notable cold temperatures were in the West on Wednesday and Thursday, where numerous daily lows were set in Montana, Colorado, Nevada, Wyoming, Oregon, and Washington. The high temperature on Thursday in Havre, Montana reached only -14°F, with a low of -28°. Ely, Nevada hit 17 degrees below zero on Wednesday, crushing the old record of 5 degrees below zero for the date. The cold air brought a hard freeze Friday morning to portions of California's Central Valley, where growers have mobilized defenses to protect fragile crops. More freezing nights are expected this weekend. Riding up the edge of this cold airmass is Winter Storm Cleon, which is spreading a nasty mix of snow, freezing rain, and sleet from Texas to the Ohio Valley. Hardest hit has been Texas, where combined sleet/freezing rain accumulations reached 1.5" in Fort Worth and 1" in Dallas Friday morning, according to the National Weather Service. Ice accumulations of 1.25" were reported in Greenwood, Arkansas, and 1" in Poteau, Oklahoma. At least 200,000 customers have lost power in Texas, and American Airlines and American Eagle were forced to cancel about 900 flights system-wide due to the bad weather in Texas. Freezing rain and significant power outages from this dangerous ice storm will likely affect a swath from Southeast Oklahoma through Central Arkansas, Southeast Missouri, Southeast Illinois, Western Tennessee, Western Kentucky, Southern Indiana, and Southwest Ohio. Just to the north of this swath if ice will be a band of 5 - 8 inches of snow. Heaviest snows so far from Cleon include:

• Minnesota: 35.3 inches, Two Harbors
• Colorado: 30 inches, Douglas Pass
• Idaho: 30 inches, Gibbonsville
• Illinois: 10 inches, Mount Vernon
• Missouri: 9 inches, Fredericktown
• Arkansas: 7 inches, Bentonville
• Indiana: 7 inches, Spencer

Figure 1. A statue of George Washington is covered with freshly fallen snow at the village in Beaver Creek, Colo., Dec. 4, 2013. (AP Photo/Charles Krupa)

New storm gathering strength over California
Once Cleon exits stage right on Saturday, we will have a new winter storm entering stage left, as Winter Storm Dion is now gathering strength over California. Dion is expected to follow a track very similar to Cleon's. Dion will bring snow of 1 - 2' to California's Sierra Mountains by Saturday, and will begin spreading snow east of the Rockies on Saturday night. Freezing rain, sleet and snow will fall from northeast Texas and southeast Oklahoma to the mid-Mississippi Valley and Ohio Valley, including Little Rock, Ark., Memphis, Tenn. and Cincinnati. Accumulations will be far less than for Cleon, but impacts could still be significant, since none of Cleon's snow and ice accumulations will have melted. The nasty weather will push into the Mid-Atlantic and Northeast Sunday into Sunday night, with Washington, D.C., Baltimore, Philadelphia and New York City all seeing a wintry mix of snow, sleet and freezing rain. However, with warmer air moving in, it appears a changeover to rain is likely late Sunday into early Monday.

Windstorm Xaver kills six in Europe
Windstorm Xaver killed at least six people and caused extensive damage in Northern Europe, after raking the area with near-hurricane force winds that brought a huge storm surge to the coasts of England, the Netherlands, Germany, and Denmark. Two people were killed by high winds in the U.K., three in Poland, and one in Denmark. Xaver's powerful northwest winds blowing along the length of the North Sea piled up a massive storm surge that was the highest since 1953 in portions of Eastern England, and the second highest of the past 200 years in Northern Germany. A storm tide 3.7 meters (12.1') above the high tide mark hit Hamburg, Germany, flooding the historic fish market and low-lying regions of the Elbe River. This storm tide was just 0.35 meters below the record set in January 1976. At Bremerhaven, Germany the storm surge peaked at 4 meters, but came at low tide. The highest storm tide was 3 meters above the high tide mark early Friday morning, falling about 0.2 meters short of the all-time record, also set in January 1976. Winds gusts as high as 92 mph (148 kph) and 98 mph (158 kph) were recorded along the Danish and German coasts, respectively. A few notable winds from the storm:

Oil platform Ula off the coast of southern Norway: sustained winds of 91 mph, gusting to 108 mph, at 2 pm local time Thursday.
Copenhagen, Denmark: sustained winds of 45 mph, gusting to 65 mph at 12:20 am Friday
Sylt, Germany: sustained winds of 58 mph at 3 am Friday
Norderney, Germany: sustained winds of 60 mph at 8 pm Thursday

Figure 2. A 14 meter (46') high, 1000 kilogram (2200 lb) Tyrannosaurus replica that was standing in front of the German climate museum Klimahaus in Bremehaven had the bolts which connected its base plate to the ground sheared off by the force of Xaver's wind Friday morning, sending the unfortunate T-Rex sliding to the edge of a quay. The T-Rex stood in a place where the air was channelled around the Klimahaus building and got greatly accelerated. Luckily, the beast had only some minor abrasions. A peak wind gust of 78 mph (126 kph) was recorded in Bremerhaven during the storm.

Figure 3. The Klimahaus T-Rex in a more festive holiday mood before the great wind storm. Credit for both images: Christine Sollmann and Michael Theusner of Klimahaus. According to Dr. Theusner, "There has been surprisingly small damage for this type of storm in Germany. This may be due to the extensive preparations and warnings that were provided to the public. I think it also played a role that "Christian" had already removed weak trees and other weak structures (roofs etc). Additionally, people were sensitized due to their experience with "Christian" and stayed home."

Figure 4. Day-night satellite image of Windstorm Xaver taken at 21 UTC Thursday December 5, 2013. Image credit: Navy Research Lab, Monterey.

Jeff Masters

Winter Weather Cleon

Mighty North Sea Storm Xaver Battering Denmark, Germany, and the Netherlands

By: JeffMasters, 4:09 PM GMT on December 05, 2013

For the first time since 2007, the massive flood gates that protect the Netherlands from the North Sea have been closed, as a mighty North Sea storm hurls a huge storm surge propelled by near-hurricane force winds against the coast of the Netherlands, Germany, and Denmark. Windstorm "Xaver", as it is called by the Free University of Berlin, has already killed one person in Scotland, where a truck driver was killed and four people were injured in an accident west of Edinburgh when high winds toppled a vehicle onto several cars. Winds gusted up to 142 mph overnight in the Scottish Highlands; many roads and bridges were closed, and all train services in Scotland were suspended; Network Rail spokesman Nick King said that "there's too much debris and too much damage to equipment to continue." At 2:55 pm local time Thursday, oil rig F3 in the North Sea about 200 km (125 miles) north of the Netherlands recorded sustained winds of 83 mph, gusting to 99 mph. These winds were recorded at an elevation of 49 meters (161 feet), so were stronger than the standard winds measured at 10 meters at most world airports. Oil rig Ula off the coast of southern Norway recorded sustained winds of 91 mph, gusting to 108 mph, at 2 pm local time. On the west coast of Denmark at St. Peter Ording Airfield, sustained winds of 58 mph were recorded at 2 pm local time. Winds at Sylt, Germany were 58 mph at 5 pm local time (see the Sylt, Germany beach webcam here.

Figure 1. Waves lash the North Sea coast at the ferry dock in Dagebuell, Germany, on December 5, 2013. (CARSTEN REHDER/AFP/Getty Images)

Figure 2. MODIS satellite image of Windstorm Xaver taken at approximately 11 UTC Thursday December 5, 2013. Image credit: NASA Worldview.

Heavy wind damage likely
A squall line with severe thunderstorms has developed along a cold front that is sweeping across Northern Europe this Thursday afternoon, and these thunderstorms are bringing intense lightning, heavy rains, and damaging winds. The European Storm Forecast Experiment is warning of the risk of tornadoes with this squall line, and damaging wind gusts of up to 90 mph (145 kph) in the severe thunderstorms. The Thursday morning 00Z run of the European model predicted that Xaver would bottom out with a central pressure near 960 mb Friday morning; the GFS model had it stronger, at 956 mb. This will make Xaver stronger the October's Windstorm "Christian" (AKA the St. Jude storm), which bottomed out at 968 mb. Christian killed 18, and did $1.4 billion in damage. It is possible that the wind damage from Xaver will approach that of Windstorm Anatol, which hit Denmark, Southwest Sweden, and Northern Germany on December 3, 1999. Anatol had sustained winds of up to 91 mph (146 kph), killed 20 people, and injured over 800. Damage was $2.6 billion (1999 dollars) in Denmark, making it the costliest disaster in Danish history.

Figure 3. Severe weather warnings for Xaver from the European Storm Forecast Experiment.

3.5-meter storm surge predicted for Germany
The maximum storm tide of Xaver will be in Germany and Denmark, and will be unusually high, since we are only two days past the new moon. Fortunately, the German coast is well protected by dikes, which are about 8 meters high, and these dikes should be able to withstand Xaver's storm surge. The German weather service storm surge forecast made Thursday morning called for a storm tide of 3.5 meters (11.5') above average high tide in Cuxhaven and Bremerhaven during the high tide cycle early Friday morning. This is about 4.8 meters above mean sea level in Bremerhaven, which will be very close to the all-time record of 5.18 m above mean sea level set there in January 1976.

German storm surge history
The deadliest flood of the last hundred years in Germany was the "North Sea flood" in 1962 (16/17 February), where many dikes broke and 340 people were killed. In the Bremerhaven area, the dikes from the 1840s were just able to withstand the storm surge but were heavily damaged. Bremerhaven had installed storm surge gates at the mouth of the river Geeste in summer 1961 as a reaction to the 1953 flood in the Netherlands. That small-scale Deltaworks saved the city. After this catastrophe, the dikes along the German coast were strengthened. Just in time, as the highest storm surge of at least the last hundred years occurred in January 1976. In Hamburg, the 1976 flood was 4.35 meters (14.3') above average high tide, which is 6.45 meters (21.2') above mean sea level. This is 75 cm higher than the storm surge of 1962, but the dikes were strong and high enough in 1976 to withstand the flood. Thanks go to Dr. Michael Theusner of the German climate museum Klimahaus for these stats.

Weather graphics and storm impacts from Storm #Xaver from Tim Ballisty @IrishEagle
Sylt, Germany webcam
‪Dagebüll‬, Germany ferry terminal webcam
Thyboroen, Denmark webcam (thanks go to wunderground member barbamz for this link.)
24-hour storm surge forecasts and actual water levels for the North Sea coast
Tide chart for Bremerhaven, Germany. The highest storm tide will occur at high tide at 1:59 UTC (2:59 CET) on Friday morning.
German weather forum
Wikipedia's list of great European windstorms.
A list of the severest storm surges at the North Sea (in German) and a not so-detailed list in English here
The Future of Intense Winter Storms, my 2010 blog post on climate change and winter storms (updated in early 2013.)

Jeff Masters

Winter Weather

Extreme Windstorm Xaver Poised to Batter Denmark and Germany

By: JeffMasters, 1:44 AM GMT on December 04, 2013

A developing extratropical low pressure system over the North Atlantic, dubbed "Xaver" by the Free University of Berlin, is predicted to "bomb" into a potent storm with winds near hurricane force that will bring damaging winds and storm tides to the coasts of Germany, the Netherlands, and Denmark on Thursday. By Thursday night, Xaver's center will cross southern Sweden, and damaging winds from the storm will sweep the coasts of Poland, Lithuania, and southern Sweden. The center of the low will pass over southern Norway, bringing strong northwest winds that will funnel down the North Sea. The European model predicts that at 18 UTC on Thursday, winds on the west coast of Denmark will be sustained near 58 mph (93 kph). Xaver will be accompanied by intense thunderstorms capable of mixing the stronger winds occurring aloft down to the surface, and wind damage may rival that of October's Extratropical Storm "Christian" (AKA the St. Jude storm), which bottomed out at 968 mb. Christian killed 18, and did $1.4 billion in damage. There is a smaller chance that the wind damage from Xaver will approach that of Windstorm Anatol, which hit Denmark, Southwest Sweden, and Northern Germany on December 3, 1999. Anatol had sustained winds of up to 91 mph (146 kph), killed 20 people, and injured over 800. Damage was $2.6 billion (1999 dollars) in Denmark, making it the costliest disaster in Danish history.

Figure 1. The European (ECMWF) model run performed at 12Z (7 am EST) on Tuesday, December 2, 2013, valid at 18Z (1 pm EST) Thursday, December 5, 2013, calls for winds in excess of 60 knots (69 mph) to affect the western coast of Denmark. The more recent 0Z Wednesday European model run has winds that are not quite as strong, about 5 mph less.

The predicted surface winds of Xaver will be similar to the ones the Netherlands experienced during the great February 1, 1953 North Sea storm that breached dikes in the Netherlands and England and killed over 2100 people. That storm bottomed out with a central pressure of 964 mb. Wednesday's 0Z European model run bottoms Xaver out at 964 mb, and the 12Z GFS is more intense, at 956 mb. However, the 1953 storm was much slower, and brought sustained winds in excess of 50 knots (57.5 mph) to the North Sea for more than 24 hours, allowing a huge storm surge in excess of 3 meters (10 feet) to pile up. In contrast, "Xaver" is expected to bring 50-knot winds to the North Sea for only about 9 hours, and the storm surge will not be as high as occurred in 1953. The maximum storm surge of Xaver will be in Germany and Denmark, farther to the east than occurred in the 1953 storm. The storm tide will be unusually high, since we are only two days past the new moon. Fortunately, the German coast is well protected by dikes, which are about 8 meters high, some even higher, and these dikes should be able to withstand Xaver's storm surge. The German weather service storm surge forecast made Wednesday morning called for a storm tide of 3 meters above average high tide in Cuxhaven, and 2.75 meters in Bremerhaven, during the high tide cycle early Friday morning.

Video 1. Winds from Windstorm "Christian" topple a tree that nearly kills a cyclist in the Netherlands on October 28, 2013.

German storm surge history
The deadliest flood of the last hundred years in Germany was the "North Sea flood" in 1962 (16/17 February), where many dikes broke and 340 people were killed. In the Bremerhaven area, the dikes from the 1840s were just able to withstand the storm surge but were heavily damaged. Bremerhaven had installed storm surge gates at the mouth of the river Geeste in summer 1961 as a reaction to the 1953 flood in the Netherlands. That small-scale Deltaworks saved the city. After this catastrophe, the dikes along the German coast were strengthened. Just in time, as the highest storm surge of at least the last hundred years occurred in January 1976. In Hamburg, the 1976 flood was 4.35 meters (14.3') above average high tide, which is 6.45 meters (21.2') above mean sea level. This is 75 cm higher than the storm surge of 1962, but the dikes were strong and high enough in 1976 to withstand the flood. Thanks go to Dr. Michael Theusner of the German climate museum Klimahaus for these stats.

Video 2. The great North Sea storm of February 1, 1953.

24-hour storm surge forecasts and actual water levels for the North Sea coast
Tide chart for Bremerhaven, Germany. The highest storm tide will occur at high tide at 1:59 UTC (2:59 CET) on Friday morning.
German weather forum
Wikipedia's list of great European windstorms.
The Future of Intense Winter Storms, my 2010 blog post on climate change and winter storms (updated in early 2013.)

Jeff Masters

Winter Weather Extreme Weather

Super Typhoon Haiyan From Ground Zero: a New Video Record

By: Josh Morgerman , 3:47 PM GMT on December 02, 2013

This guest post and video is from veteran storm chaser Josh Morgerman of West Hollywood, California, who rode out Super Typhoon Haiyan in Tacoloban in the Philippines. Josh is the founder of of, and has been chasing tropical cyclones since 1991.

Super Typhoon Haiyan (Yolanda to the Filipinos) is one of the biggest weather catastrophes of the past decade. A Category-5 storm making a direct hit on a city of 220,000 is going to make news.

I chased Haiyan to ground zero--Tacloban City--where I rode out the cyclone with fellow storm chasers James Reynolds and Mark Thomas. Our location: Hotel Alejandro, a four-story, solid-concrete building in the heart of downtown, 26 feet above sea level. (Coordinates:11.2414N 125.0036E.)

A safe place. Or so we thought.

I just released this short video that tells the story of that terrible morning--in graphic, frightening detail.

As the wind rose to a scream, as windows exploded and doors blew off, as the building trembled from the impact of flying debris and as children became hysterical, a massive storm surge swept the entire downtown, inundating the hotel and sending guests scrambling for their lives. My fellow chasers and I had to throw down our cameras and pull elderly and disabled guests out through the smashed windows of flooded rooms.

And we were the lucky ones in Tacloban City.

While whole blocks were reduced to rubble, our building stayed standing. And while thousands died--including people on our very block--I’m very happy to say that everyone in our hotel (and everyone you see in my video) survived. This includes the family you see struggling across the storm surge to reach our hotel. (One of the most serious injuries was actually on our own team: while trying to rescue a trapped guest, Mark tore open his leg on underwater wreckage, and weeks later he’s making a very slow recovery at home in Taipei.)

Video as Meteorological Record
My video’s many viewers have reacted strongly to the raw power of the storm and the spectacle of ordinary people trying to survive a life-and-death situation. This is understandable.

But I want to also point out that my video is a useful meteorological record.

When I chase, I always stamp my video footage with the exact local time, so afterward I can compare conditions on the ground with other data--to try and understand what happened.

So my Super Typhoon Haiyan video serves as detailed chronology of the event. Combining it with air-pressure and storm-surge data I collected during the event, we can learn a lot about this unique and ferocious cyclone.

Haiyan Video Chronology
First off, here are some important events and details to notice in the video:

6:47 am. The eyewall sweeps into the city. Winds rapidly increase and rain becomes very heavy. Notice the trees are full and green.

7:08 am. In narration, I note the pressure is 962 mb. This was close to the lowest values my devices recorded (960.8 mb and 960.3 mb at 7:12 am and 7:20 am, respectively)--meaning the center was passing just south of the city and making its closest approach about this time.

7:13-7:25 am. The winds reach a peak. Tornado-like conditions engulf downtown. We never experience a calm--meaning the eye misses us to the south.

7:44 am. The storm surge sweeps in suddenly. The street is completely flooded, whereas just minutes earlier, we hadn’t noticed any water.

8:00-8:30 am. Water is up to the first-floor door handles and windows. (You can see this in the rescue shot--donated by Earth Uncut TV--that follows 7:57 am. It’s not time-stamped but certainly occurred between 8 and 8:30 am.)

8:45-8:46 am. The storm is dying down. Winds are slacking and the water is already noticeably receding--it’s much lower against the doors and windows.

8:57-9:00 am. All deciduous trees across the city are completely stripped--with no leaves. (Palms performed a little better.)

Figure 1. Haiyan, the aftermath: extreme storm surge damage in Tacloban. Image credit: Josh Morgerman,

Using the above video events and details—along with other data—we can draw a few conclusions about Super Typhoon Haiyan when it made landfall in Leyte, just south of Tacloban City:

The typhoon’s core was small. As per the video, the storm didn’t last long. Winds in the city didn’t become violent until only 30 minutes before the center’s closest approach, and really destructive winds lasted only 2 hours (~6:45 - 8:45 am). Even taking into account Haiyan’s fast forward motion, it’s clear the storm was on the small side--despite news reports to the contrary. It’s a testament to Haiyan’s incredible ferocity that it was able to completely devastate Tacloban City in such a short time.

The northeast eyewall was strongest. The storm was moving west-northwest and the highest winds seemed to occur during and after the lowest pressure. This is consistent with the radar imagery, which showed the strongest convection in the northeast quad.

Tacloban City experienced extremely high winds--at least Cat 3 and possibly Cat 4, since we saw complete defoliation and evidence of debarking of deciduous trees. This is especially impressive given that the highest winds didn’t last long--and I should point out that it’s exceedingly unusual for an urban area to experience such intense winds. While Haiyan was a Cat-5 storm and Tacloban City was squarely in its north eyewall, we believe the RMW (radius of maximum winds) passed just south of downtown.

The storm surge was tremendous, fast-moving, and short-duration. USGS data and other sources indicate the elevation at our location was 26 feet. Since the hotel flooded to a depth of 4 feet, that suggests the surge may have been an incredible 30 feet! (Even if we’ve overestimated our elevation by 10 feet, that’s still a huge 20-foot surge.) But it didn’t last long. It swept in very suddenly around 7:45 am and was already receding by 8:45--meaning it did its deadly work with incredible speed. This is very different than Hurricane Ike, a large storm that caused large-scale inundation more than a day before landfall.

Josh Morgerman,


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Category 6™


Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather