Category 6™

The Exceptional U.S. Wildfire Season of 2012

By: JeffMasters, 5:11 PM GMT on December 31, 2012

The 2012 U.S. fire season was the 3rd worst in U.S. history, with 9.2 million acres burned--an area larger than the state of Maryland. Since the National Interagency Fire Center began keeping records in 1960, only two years have seen more area burned--2006, when 9.9 million acres burned, and 2007, when 9.3 million acres burned. Although the 2012 fire season was close to a record for most acreage burned, the total number of fires--55,505--was the lowest on record, going back to 1960, said scientists at a December 2012 press briefing at the American Geophysical Union meeting in San Francisco. The average U.S. fire size in 2012 was the highest on record. A September 18, 2012 report, The Age of Western Wildfires, published by the non-profit research group Climate Central, found that the number of large and very large fires on Forest Service land is increasingly dramatically. Compared to the average year in the 1970s, during the past decade there were seven times as many fires larger than 10,000 acres each year, and nearly five times as many fires larger than 25,000 acres. On average, wildfires burn twice as much land area each year as they did 40 years ago, and the burn season is two and a half months longer than 40 years ago. The increase in large fires is correlated with rising temperatures and earlier snow melt due to climate change, but fire suppression policies which leave more timber to burn may also be a factor.

The Top 5 U.S. Wildfires of 2012
Whitewater-Baldy Complex Fire, New Mexico: Largest fire in New Mexico history
The Whitewater-Baldy Complex Fire started as two fires that merged, both caused by lightning. The Whitewater fire was first detected on May 16th, and the smaller Baldy fire was detected a few days earlier on May 9th. These fires then merged on May 24th and together burned a total of 297,845 acres until it was 100% contained on July 23th. Mid-July rain showers helped fire crew contain this fire. This fire was difficult to contain due to rugged terrain with gusty winds, and relative humidity less than 3%. The fire consumed timber, mixed conifer, poderosa pine, pinon/juniper, and grasses. The suppression costs of the Whitewater-Baldy Complex Fire surpassed $23 million, according to the GACC. This is the largest fire in New Mexico history, which surpassed the previous record of 150,000 acres consumed by the Las Conchas Fire in 2011.


Figure 1. Wunderphoto of Whitewater-Baldy Complex Fire submitted by AZMountaineer21.


Figure 2. Satellite image showing the complex nature of the Whitewater-Baldy fire with multiple hot spots in red outlines with multiple smoke plumes. Image courtesy of NASA's MODIS Aqua on June 7th, 2012.

Rush Fire, California: 2nd largest in California history
The Rush Fire started from lightning on Aug. 12th and burned through Aug. 30th, consuming 315,577 acres of northeastern California portions of western Nevada. The rapid and uncontrollable fire spread was due to extremely difficult terrain, gusty winds, and extremely dry grass, sagebrush, and junipers. Fire crews reported, "Live sage brush was as dry as dead sage brush." This fire was rated a major threat to federally protected wild horses, burros, and grouse by the BLM Eagle Lake Field Office. Once this fire reached into Nevada, where it burned over 43,000 acres, it threatened a major natural gas line as well as power transmission lines. This fire cost the U.S. approximately a total of $15 million. The portion of the fire in California reached 271,911 acres, and now constitutes the second largest California fire in modern history. The largest California fire remains the Cedar Fire in 2003, which consumed 273,246 acres.


Figure 3. Progression of the Rush Fire, August 12 - 20, 2012. Image courtesy of Inciweb.org, Rush Fire maps.

Waldo Canyon Fire, Colorado: most expensive in Colorado history
The Waldo Canyon Fire was the most expensive wildfire in Colorado history, costing $353 million, according to the Rocky Mountain Insurance Information Association. The cause of the fire is still under investigation, but investigators have determined that it was started within 3 miles of the Waldo Canyon trail head, off of U.S. 24, and was human-caused. The burn started on June 23rd and burned through July 10th, burning a total of 18,247 acres of brush, mountain shrub, oak, grass, pinion juniper, ponderosa pine, douglas fir, spruce, and limber pine. This fire was a major threat to neighborhoods and homes, as it started only four miles from Colorado Springs. Approximately 347 homes were burned and 2 people were killed by the Waldo Canyon Fire. Due to the proximity of this fire to nearby neighborhoods, over 32,000 residents were evacuated.


Figure 4. Image showing how close the Waldo Canyon fire was to homes in Colorado Springs. AP photo.


Figure 5. Flames from the Waldo Canyon Fire rolling down a hillside approaching a Colorado Springs neighborhood. AP photo.

High Park Fire, Colorado: 2nd largest in Colorado history
The High Park Fire was caused by lightning and first detected on June 9th in the mountains west of Fort Collins. The fire burned 87,284 acres of timber, grass, and brush until it was 100% contained on July 1st, making this the second largest fire in Colorado history. The largest Colorado fire remains the Hayman Fire, which burned 137,760 acres in 2002. The High Park Fire killed one person, and was briefly the most destructive fire in Colorado history, after destroying 259 homes. However, this record was quickly surpassed by the Waldo Canyon Fire just a few days later.


Figure 6. Plane throwing fire retardant onto the High Park Fire. AP photo.


Figure 7. The huge plume of the High Park Fire seen from a neighborhood. Wunderphoto submitted by turbguy.

Chips Fire, California: $55 million in suppression costs
California's Chips Fire began on July 29th and burned a total of 75,431 acres in northern California, including 48,297 acres of the Plumas National Forest, 18,374 acres of Lassen National Forest, and 8,762 acres of privately owned land. The cause of the fire is unknown. The fire forced hikers on the Pacific Crest Trail to bypass this section by hiking Hwy 70/89 or by taking a bus and skipping this section all together. The fire was contained Aug. 31st, with a total of $55 million in suppression costs. Mainly timber was consumed in this fire.


Figure 8. Satellite image of fires in northern California on August 11 2012, including the Chips fire. Image courtesy of NASA's MODIS Aqua on August 11, 2012.


Figure 9. Burn scar from the Chips Fire. Burned vegetation appears in red, unburned areas are in green. Image courtesy of NASA's Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite on September 1, 2012.

Western U.S. wildfires expected to increase due to climate change
Expect a large increase in fires over much of the globe late this century due to climate change, says research published this June in the Journal Ecosphere. Using fire models driven by output from sixteen climate models used in the 2007 IPCC report, the researchers, led by Max Moritz of UC Berkeley, found that 38% of the planet should see increases in fire activity over the next 30 years. This figure increases to 62% by the end of the century. However, in many regions where precipitation is expected to increase--particularly in the tropics--there should be decreased fire activity. The scientists predicted that 8% of Earth will see decreases in fire probability over the next 30 years, and 20% will see decreases by the end of the century. The models do not agree on how fire danger will change for a large portion of the planet--54% for the period 2010 - 2039, and 18% for the period 2070 - 2099. Six key factors were found to control fire probabilities in the models. Most important was how much vegetation there was (NPP, Net Primary Productivity). Three other factors, about half as important, were precipitation of driest month, mean temperature of warmest month, and the difference between summer and winter temperature. Two other minor factors were mean temperature of wettest month, and annual precipitation. The authors found that future fire occurrence appears to primarily be a function of available moisture in many areas, and that the expected global increase in temperature of 3.5°C used in the models will not become the single dominant control on global wildfire. In the U.S., the regions most at risk of increased fires are the tundra regions of northern Alaska, and the West, with Arizona and Colorado at particularly high risk.

Related: Wildfires in the U.S. will be at least twice as destructive by 2050, burning around 20 million acres nationwide each year, according to a federal report released by the U.S. Department of Agriculture in 2012.


Figure 10. Predicted fractional change in fire probability for the period 2010 - 2039 (top) and 2070 - 2099 (bottom) for the average of sixteen climate models used for the 2007 IPCC report. For the 2010 - 2039 period, the models agree that 8% of Earth will see decreases in fire probability, 38% will see increases, and the models are too uncertain to tell for the other 54%. For the 2070 - 2099 period, the models agree that 20% of Earth will see decreases in fire probability, 62% will see increases, and the models are too uncertain to tell for the other 18%. Image credit: Climate change and disruptions to global fire activity, Moritz et al., 2012, from the journal Ecosphere.


Coolest fire video of 2012: A fire tornado in Curtin Springs, Australia, from mid-September, 2012. NOAA comments: "While rare, fire tornadoes (also known as fire whirls) generally form when superheated air near the surface of a large fire zone rises rapidly in an airmass where sufficient horizontal or vertical vorticity (spin in the atmosphere) is also present. Much like a dust devil or whirlwind, the rapidly rising air above a wildfire can accelerate and turn the local vorticity into a tight vertical vortex, now composed of fire instead of dust."

Kari Kiefer and Jeff Masters

Fire Climate Change

Great Drought of 2012 continuing into 2013

By: JeffMasters, 5:01 PM GMT on December 28, 2012

Rain and snow from the massive winter storm that swept across the nation over the past week put only a slight dent in the Great Drought of 2012, according to the latest U.S. Drought Monitor report. The area of Iowa in extreme or exceptional drought fell 9 percentage points to 32 percent, thanks to widespread precipitation amounts of 0.5" - 1.5". However, the area of the contiguous U.S. covered by moderate or greater drought remained virtually unchanged from the previous week, at 61.8%. According to NOAA's monthly State of the Drought report, the 61.8% of the U.S. covered by drought this week was also what we had during July, making the 2012 drought the greatest U.S. drought since the Dust Bowl year of 1939. (During December of 1939, 62.1% of the U.S. was in drought; the only year with more of the U.S. in drought was 1934.) The Great Drought of 2012 is about to become the Great Drought of 2012 - 2013, judging by the latest 15-day precipitation forecast from the GFS model. There is a much below-average chance of precipitation across the large majority of the drought region through the second week of January, and these dry conditions will potentially cause serious trouble for barge traffic on the Mississippi River by the second week of January. The river level at St. Louis is currently -3.6', which is the 9th lowest level of the past 100 years. The latest NOAA river level forecast calls for the river to fall below -5' by January 4. This would be one of the five lowest water levels on record for St. Louis. At this water level, the river's depth will fall to 9' at Thebes, Illinois, which is the threshold for closing the river to barge traffic. The Army Corps of Engineers is working to dredge the river to allow barge traffic to continue if the river falls below this level, but it is uncertain if this will be enough to make a difference, unless we get some significant January precipitation in the Upper Mississippi watershed. The river is predicted to set a new all-time low by January 13 (Figure 4.)


Figure 1. The December 25, 2012 U.S. Drought Monitor showed that approximately 62% of the contiguous U.S. was in moderate or greater drought.



Figure 2. Predicted 7-day precipitation for the period ending on Friday, January 4. Very few regions of the main U.S. drought area are predicted to receive as much as 0.5" of precipitation (dark green color.) Image credit: NOAA.

Long-term drought outlook
NOAA's December 20 Seasonal Drought Outlook called for drought to persist over at least 80% of the U.S. drought area through the end of March. I don't see any signs of a shift in the fundamental large-scale atmospheric flow patterns during the past few weeks, or in the model forecasts for the coming weeks, and it is good bet that drought will be a huge concern as we enter spring. NOAA's Climate Prediction Center predicts an increased chance of drier than average conditions over southwestern portions of the drought region during the coming three months. In general, droughts are more likely in the Central U.S. when warmer than average ocean temperatures prevail in the tropical Atlantic, with cooler than average ocean temperatures in the tropical Eastern Pacific (La Niña-like conditions.) This is the current situation, though the equatorial tropical Pacific is only slightly cooler than average (0.2°C below average as of December 24). Most of the Midwest needs 3 - 9" of precipitation to pull out of drought.


Figure 3. Amount of precipitation needed to bust drought conditions over the U.S., according to NOAA's Climate Prediction Center. Eastern Oklahoma and Western Arkansas need the most rain, 9 - 15".


Figure 4. The latest NOAA river level forecast calls for the Mississippi River to fall below -5' at St. Louis by January 4. At this level, the river may close to barge traffic due to low water. By January 13, the river is expected to fall to its lowest level on record, -6.2'. The record was set in January 1940, after the great Dust Bowl droughts of the 1930s.


Figure 5. This Nov. 28, 2012 photo provided by The United States Coast Guard shows a WWII minesweeper on the Mississippi River near St. Louis, Missouri. The minesweeper, once moored along the Mississippi River as a museum at St. Louis before it was torn away by floodwaters in 1993, is normally completely under water. However, it has become visible--rusted but intact--due to near-record low river levels on the Mississippi. (AP Photo/United States Coast Guard, Colby Buchanan)

Links:
My post on Lessons from 2012: Droughts, not Hurricanes, are the Greater Danger discussed how drought is our greatest threat from climate change.

Ricky Rood blogs about the Dust Bowl

Have a great weekend, everyone!

Jeff Masters

Drought

Two EF-3 tornadoes confirmed from Christmas Day; heavy snows hit 19 states

By: JeffMasters, 4:04 PM GMT on December 27, 2012

Winter Storm Euclid continues its U.S. tour today, and is pounding New England with heavy snows, high winds, and coastal flooding. The impressive storm set a record for most tornadoes spawned on Christmas Day, as 13 tornadoes have been confirmed (with at least 12 other suspected tornadoes still unrated.) The previous record for most tornadoes on Christmas Day was twelve, back in 1969. Yesterday, Euclid spawned an additional confirmed tornado in North Carolina. No more tornadoes are expected today.

Euclid has dumped more than six inches of snow in 19 states--Arkansas, Indiana, Illinois, Missouri, Oklahoma, Kentucky, Maryland, Michigan, Ohio, West Virginia, Connecticut, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Vermont, Maine, and Texas. According to the latest NWS Storm Summary, the greatest snowfall so far has been at Albion, Illinois, where 18.3" has fallen. This will likely be exceeded in Maine, where up to two feet of snow is expected before the storm ends on Friday. Fortunately, the tornadoes from the storm are not being blamed for any deaths, though strong thunderstorm winds killed two people on Christmas Day due to falling trees. At least two of the Christmas Day tornadoes were rated EF-3. The EF-3 that hit Pennington, in Southeast Texas, completely destroyed a feed store and a restaurant, and had winds up to 150 mph. The other EF-3 hit McNeil, Mississippi, and was rated a weak EF-3 with winds of 140 mph. The tornado cut a path 24 miles long, injured 8 people, and damaged or destroyed 46 homes. Only four other EF-3 tornadoes have been recorded on Christmas Day since 1950, according to the Tornado History Project. The latest in the year an EF-3 tornado has touched down is December 31. This occurred just two years ago, in 2010, when five EF-3 tornadoes raked Arkansas, Missouri, and Illinois.

Powerful southwest winds from the storm created a significant storm surge of 5 - 6 feet which caused moderate coastal flooding this morning at Sandy Hook, NJ and King's Point, NY. The storm surge in New York City at Battery Park reached 5.9 feet, but occurred near low tide, so only minor flooding was reported. Some peak wind gusts from the storm:

66 mph at Tuckerton Shores, NJ
64 mph at Dover AFB, Delaware
64 mph at Boone, NC
60 mph at Eatons Neck, NJ


Figure 1. Damage from the tornado that hit Maxie, MS on Christmas Day was EF-2. This tornado did EF-3 damage near McNeil, MS. Image credit: NWS Jackson.


Figure 2. Storm reports from Christmas Day, 2012, from NOAA's Storm Prediction Center, show a preliminary 35 tornado reports.


Video 1. This remarkable video from surveillance cameras at a Walgreen's in Mobile, AL during the December 25, 2012 EF-2 tornado show cars and debris flying through the parking lot, and it is fortunate no one was killed. I like the reaction of the guy pushing his cart outside the door into the tornado. Whoa! Not a good idea! This was the second tornado to hit Mobile in the past week, as an EF-1 tornado also hit the city on December 20.

Our new featured blogger, meteorologist Lee Grenci, offers a detailed analysis of the Christmas Day tornado outbreak.

Jeff Masters

Winter Weather Tornado

Heavy snow and largest Christmas tornado outbreak on record slam U.S.

By: JeffMasters, 7:33 PM GMT on December 26, 2012

The most impressive U.S. December snowstorm in two years is powering across the eastern third of the country today, bringing blizzard conditions to Indiana and Ohio and severe thunderstorms to eastern North Carolina. The 28 preliminary tornadoes that touched down yesterday will likely put December 25, 2012 in first place for largest Christmas tornado outbreak in U.S. history. Fortunately, the tornadoes are not being blamed for any deaths, though strong thunderstorm winds have killed two people due to falling trees. Dozens of people have been injured due to the severe weather--25 in Mississippi alone. The parent storm has dumped more than 8 inches of snow in six states--Arkansas, Indiana, Illinois, Missouri, Oklahoma, and Texas. According to the latest NWS Storm Summary, the greatest snowfall so far has been at Morrilton, Arkansas, where 13.5" has fallen. Tornado watches are posted today in Eastern North Carolina, where NOAA's Storm Prediction Center has indicated a "Slight Risk" of severe weather exists. This is one level of alert below the "Moderate Risk" of severe weather that existed on Christmas Day for Louisiana, Mississippi, and Alabama. As of 2 pm EST on December 26, no tornadoes had been reported for the day, though several tornado warnings had been issued for North Carolina.


Figure 1. Winter Storm Euclid at 1:25 pm EST Wednesday, December 26, 2012. Image credit: NASA/GSFC.


Figure 2. Preliminary storm reports from Christmas Day, 2012, from NOAA's Storm Prediction Center show as many as 28 tornado reports.

History of Christmas-time tornado outbreaks
Serious tornado outbreaks in the winter are uncommon, particularly so during Christmas. According to the Tornado History Project there have been eight Christmases since 1950 with tornadoes. The most recent Christmas with tornadoes was in 2006, when six twisters touched down in Florida and Georgia. The most tornadoes ever recorded on Christmas Day was twelve, back in 1969. With 28 preliminary tornadoes reported yesterday, it appears very likely that December 25, 2012 will rank in first place for most tornadoes ever recorded on Christmas Day. It is possible that the tornado that hit Maxie, MS yesterday will be rated an EF-3, tying it for strongest Christmas tornado on record. The strongest Christmas tornadoes on record were F-3s that occurred in 1964 and 1969.


Video 1. A tornado is caught on video from the top of a Holiday Inn crossing through Mobile, Alabama on December 25, 2012. Preliminary NWS damage surveys have rated this at least an EF-1 tornado. Here is another YouTube video of the Mobile tornado.

Wunderground meteorologists Angela Fritz and Shaun Tanner are also blogging on this impressive storm, and have more info on the history of Christmas-time tornado outbreaks.

Jeff Masters

Winter Weather Tornado

Top Ten U.S. Weather Events of 2012

By: JeffMasters, 5:04 AM GMT on December 21, 2012

It was another year of incredible weather extremes unparalleled in American history during 2012. Eleven billion-dollar weather disasters hit the U.S., a figure exceeded only by the fourteen such disasters during the equally insane weather year of 2011. I present for you now the top ten weather stories of 2012, chosen for their meteorological significance and human and economic impact.

Video 1. Hour-by-hour animation of infrared satellite images for 2012. The loop goes in slow-motion to feature such events as Hurricane Sandy, the June Derecho, Summer in March, and other top weather events of 2012. The date stamp is at lower left; you will want to make the animation full screen to see the date. Special thanks to wunderground's Deb Mitchell for putting this together!

1) Superstorm Sandy
Hurricane Sandy was truly astounding in its size and power. At its peak size, twenty hours before landfall, Sandy had tropical storm-force winds that covered an area nearly one-fifth the area of the contiguous United States. Sandy's area of ocean with twelve-foot seas peaked at 1.4 million square miles--nearly one-half the area of the contiguous United States, or 1% of Earth's total ocean area. Most incredibly, ten hours before landfall (9:30 am EDT October 29), the total energy of Sandy's winds of tropical storm-force and higher peaked at 329 terajoules--the highest value for any Atlantic hurricane since at least 1969, and equivalent to five Hiroshima-sized atomic bombs. At landfall, Sandy's tropical storm-force winds spanned 943 miles of the the U.S. coast. No hurricane on record has been larger. Sandy's huge size prompted high wind warnings to be posted from Chicago to Eastern Maine, and from Michigan's Upper Peninsula to Florida's Lake Okeechobee--an area home to 120 million people. Sandy's winds simultaneously caused damage to buildings on the shores of Lake Michigan at Indiana Dunes National Lake Shore, and toppled power lines in Nova Scotia, Canada--locations 1200 miles apart! Sandy made landfall near Atlantic City, NJ on October 29, with sustained winds of 80 mph and a central minimum pressure of 946 mb--the lowest pressure on record along the Northeast coast. The Battery, in New York City Harbor, had an observed water level of 13.88 feet, besting the previous record set by Hurricane Donna in 1960 by 3 feet. Sandy also brought torrential rainfall to the Mid-Atlantic, with over 12 inches of rain observed in parts of Maryland. In addition, Sandy generated blizzard conditions for the central and southern Appalachians with more than a foot of snow falling in six states from North Carolina to Pennsylvania, shattering October snow records. Over 130 fatalities were reported and over 8.5 million customers lost power--the second largest weather-related power outage in U.S. history, behind the 10 million that lost power during the Blizzard of 1993. Damage from Sandy is estimated at $62 billion.


Figure 1. Cabs lie flooded on October 30, 2012, in Hoboken, NJ, in the wake of Hurricane Sandy. AP photo: Charles Sykes.

2) Warmest Year on Record
Spring, March, July, and the annual temperature were all warmest on record in the contiguous U.S. July was the warmest month of any month in the 1,400+ months of the U.S. data record, going back to 1895. The spring temperature departure from average was the largest on record for any season, and March temperatures had the second largest warm departure from average of any month in U.S. history. All-time hottest temperature records were set over approximately 7% of the area of the contiguous U.S., according to a database of 298 major U.S. cities maintained by wunderground's weather historian, Christopher C. Burt. Given the very warm December temperatures so far, the final 2012 annual temperature is likely to break the previous warmest year on record (1998) by at least 0.7°F--a colossal margin to break an annual record by. It is likely that 15 states will end up with their warmest year on record in 2012, and 42 states will have a top-ten warmest year.


Figure 2. One of 2012's incredibly hot days: high temperatures on August 1 in Oklahoma from the Oklahoma Mesonet. It was the hottest day in Oklahoma since August 1936, with more than half of the state recording temperatures of 110° or higher. Oklahoma City hit 112°, tied for the city's 3nd highest temperature since record keeping began in 1890. The only hotter days occurred two days later--on August 3, 2012--and back on August 11, 1936 (113°.)

3) The Great Drought of 2012
The Great U.S. Drought of 2012 may well turn out to be the biggest weather story of 2012, since its full impacts have not yet been realized. The area of the contiguous U.S. in moderate or greater drought peaked at 61.8% in July--the largest such area since the Dust Bowl drought of December 1939. The heat and dryness resulted in record or near-record evaporation rates, causing major impact on corn, soybean and wheat belts in addition to livestock production. Drought upstream of the Lower Mississippi River caused record and near-record low stream flows along the river in Mississippi and Louisiana, resulting in limited river transportation and commerce. Crop damages alone from the great drought are estimated at $35 billion. As the total scope of losses is realized across all lines of business in coming months, this number will climb significantly.


Figure 3. Corn in Colby, Kansas withers in the Great Drought of 2012 on May 27. Image credit: Wunderphotographer treeman.

4) Wildfire Season of 2012
The 2012 U.S. fire season was the 3rd worst in U.S. history, with 9.2 million acres burned--an area larger than the state of Maryland. Since the National Interagency Fire Center began keeping records in 1960, only two years have seen more area burned--2006, when 9.9 million acres burned, and 2007, when 9.3 million acres burned. New Mexico had its largest fire in state history, Colorado its most destructive and 2nd largest in state history, and Oregon had its largest fire since the 1860s. More than 3.6 million acres burned in the U.S. during August--the most on record for any August in recorded history.


Figure 4. Wunderphoto of Whitewater-Baldy Complex Fire of 2012, the largest fire in New Mexico history. Wunderphoto submitted by AZMountaineer21.

5) March 2 - 3 Tornado Outbreak
A massive tornado outbreak of stunning violence swept through the nation's midsection March 2 - 3, spawning deadly tornadoes that killed 41 people. Hardest hit were Kentucky and Southern Indiana, which suffered 22 and 13 dead, respectively. The scale of the outbreak was exceptional, with 70 tornadoes touching down in eleven states, from southern Ohio to southern Georgia. At one point, 31 separate tornado warnings were in effect during the outbreak. An area larger than Nebraska--81,000 square miles--received tornado warnings, and tornado watches were posted for 300,000 square miles--an area larger than Texas. The outbreak spawned two EF-4 tornadoes, one which devastated Henryville, Indiana, and another that plowed through Crittenden, Kentucky. Total damage was estimated at $4 billion.


Figure 5. A school bus mangled by the EF-4 Henryville, Indiana tornado of March 2, 2012. Image credit: NWS Louisville, Kentucky.

6) June 29 Multi-State Derecho
A violent line of organized severe thunderstorms called a derecho swept across the U.S. from Illinois to Virginia on June 29, damaging houses, toppling trees, bringing down power lines. The storms killed 22 people, and left at least 3.4 million customers without power. The thunderstorms in a derecho (from the Spanish phrase for "straight ahead") create violent winds that blow in a straight line. The derecho was unusually intense due to extreme heat that set all-time records at ten major cities on the south side of the derecho. This heat helped create an unstable atmosphere with plenty of energy to fuel severe thunderstorms. At least 38 thunderstorms in the derecho generated wind gusts in excess of hurricane force, making the derecho one of the most severe derechoes on record. Total damage was estimated at $3.75 billion.


Figure 6. Turbulent clouds gather over Mettawa, Illinois on June 29, 2012, as the historic 2012 derecho begins to organize. Image credit: Wunderphotographer LarrySmit.

7) Hurricane Isaac
Hurricane Isaac slowly lumbered ashore near the mouth of the Mississippi River on August 28 as a Category 1 Hurricane with 80 mph winds. Isaac's large size and slow motion caused a storm surge more characteristic of a Category 2 hurricane--up to eleven feet--but New Orleans' new $14.5 billion levee upgrade held against Isaac's surge. The surge moved up the Mississippi River in Plaquemines Parish near Port Sulphur, causing overtopping of the levees and flooding of homes in the mandatory evacuation areas behind the levees. These levees were not part of the $14.5 billion levee upgrade. Isaac brought torrential rainfall, with more than twenty inches observed in some areas of New Orleans. Isaac also provided some drought relief to the Lower Mississippi and Ohio Valleys. Isaac dumped up to 18" of rain in Florida, and disrupted the 2012 Republican Convention in Tampa. Isaac did $2 billion in damage.


Figure 7. Tropical Storm Isaac on August 28, a few hours before it intensified into a hurricane.

8) The Non-Winter of 2011-2012
"Flowers are sprouting in January in New Hampshire, the Sierra Mountains in California are nearly snow-free, and lakes in much of Michigan still have not frozen. It's 2012, and the new year is ringing in another ridiculously wacky winter for the U.S. In Fargo, North Dakota yesterday, the mercury soared to 55°F, breaking a 1908 record for warmest January day in recorded history. More than 99% of North Dakota had no snow on the ground this morning, and over 95% of the country that normally has snow at this time of year had below-average snow cover." That was the opening of my January 6, 2012 blog post, called "Remarkably dry and warm winter due to record extreme jet stream configuration." The contiguous U.S. saw its 3rd lowest snow cover on record during both winter and spring, and the winter of 2011 - 2012 was the 4th warmest and 24th driest winter in U.S. history, going back to 1895. A primary cause of this warm and snowless winter was the most extreme configuration of the jet stream ever recorded, as measured by the North Atlantic Oscillation (NAO). The NAO index was +2.52 in December 2011, which was the most extreme difference in pressure between Iceland and the Azores ever observed in December (records of the NAO go back to 1865.) The positive NAO conditions caused the Icelandic Low to draw a strong south-westerly flow of air over eastern North America, preventing Arctic air from plunging southward over the U.S.


Figure 8. Flowers sprouting on January 1, 2012 in Keene, New Hampshire, thanks to unusually warm December temperatures and lack of snow. Image credit: Wunderphotographer lovne32.


9) April 30 - May 1 Severe Weather Outbreak
A severe weather outbreak in the Ohio Valley April 30 - May 1 caused 38 tornadoes and $4 billion in damage.

10) Late-Spring Freeze: Northeast/Midwest
After the record-warm "Summer in March" weather in the Great Lakes and Northeast, an April freeze damaged crops across the region. New York's fruit production was the lowest since 1948, and it was the worst fruit season for Michigan since 1945. Damage in Michigan alone was estimated at $500 million.



Honorable Mentions (text courtesy of NOAA's National Climatic Data Center, with damage estimates from AON Benfield):

Severe Weather Outbreak (May):
A strong cold front moving through the country on May 25 - 30 spawned 27 tornadoes from Texas to the Northeast. Damage was estimated at $2.5 billion, much of it from hail.

Severe Weather Outbreak (April):
A tornado outbreak on April 13 - 14 in the Plains spawned 98 tornadoes and caused at least 6 fatalities. Damage was estimated at $1.75 billion.

Severe Weather Outbreak (June):
Several days of severe storms across the Southwest spawned 25 tornadoes from June 6 - 12. Significant hail damage occurred across the Rocky Mountain Front Range, with total damage estimated at $1.75 billion.

Tropical Storm Debby/Wet Florida (June):
Heavy rains from Tropical Storm Debby in early June caused damage estimated at $310 million, but Debby's rains helped break a drought in Northern Florida. Florida had its wettest summer on record, partially due to Debby.

Duluth Flooding (June):
Training thunderstorms caused record flooding in and around Duluth Minnesota on June 20, with over 8 inches of rainfall observed in 24 hours in parts of the city. Two rivers in the Duluth area, the Nemadji and St. Louis, reported their highest flood heights on record. Damage was estimated at $175 million.

Pacific Northwest Winter Storm (January):
A massive winter storm impacted the Pacific Northwest on January 18 - 23. Huge amounts of rain and snow fell, and hurricane-force wind gusts knocked out power to 250,000 customers. Damage was estimated at $100 million.

Hawaiian Hail Storm (March):
On March 9, a cut-off low pressure system impacted the Hawaiian Islands, bringing heavy rainfall and severe thunderstorms. A rare EF-0 tornado hit the towns of Lanikai and Kailua on Oahu, causing minor damage. Another storm dropped a hailstone measuring 4.25 inches long, 2.25 inches tall, and 2 inches wide--the largest hailstone on record for Hawaii. Damage from the storms was estimated at $37 million.

Near-Record Low Great Lakes Levels (by end of 2012):
Record warm temperatures throughout 2012 combined with low precipitation and low winter ice cover created high evaporation rates across the Great Lakes. In December, Lakes Michigan and Huron had fallen to within inches of the all-time record low lake levels set back in 1964. Low lake levels have a significant impact on recreational and commercial boating as well as tourism.

Slow Tornado Year (annual):
Despite an active March, 2012 saw relatively low tornado numbers compared to recent history.

Mount Evans Tornado (July):
A high elevation tornado was observed along the slope of Mount Evans at 11,900 feet--the second highest observed tornado in the U.S.

Alaska Cold Winter/Snow Record (winter):
Several Alaskan locations had their coldest January on record. The monthly average temperature at Bettles, AK was -35.6°F. The statewide average January temperature was record cold--14°F below average. Record snow (134.5 inches) fell in Anchorage during the winter season, breaking the previous record set in 1954 - 55.

Alaskan Storms and Flooding (September):
Several large extratropical cyclones impacted Alaska during September. Significant flooding occurred along the Sustina River and along its tributaries, causing the worse flooding in 30 years. Over 800 structures and dozens of homes were damaged or destroyed. The storms also brought early snowfall to southern portions of the state.

Death Valley sets world record for highest minimum temperature
On Thursday morning, July 12, 2012 the low temperature at Death Valley, California dropped to just 107°F (41.7°C), after hitting a high of 128° (53.3°C) the previous day. Not only did the morning low temperature tie a record for the world's warmest low temperature ever recorded, the average temperature of 117.5°F was the world's warmest 24-hour temperature on record. According to weather records researcher Maximiliano Herrera, the only other place in the world to record a 107°F low temperature was Khasab Airport in the desert nation of Oman on June 27, 2012.

NOAA's National Climatic Data Center will release their top-ten list of U.S. weather events of 2012 on Tuesday, January 8, 2013.

Have a great holiday, everyone! I'll be back on December 26 with a new post.

Jeff Masters

Climate Summaries Extreme Weather

Winter Storm Draco ends record snowless streaks across Midwest

By: JeffMasters, 5:03 PM GMT on December 19, 2012

Winter Storm Draco is powering up over the Upper Midwest, and is poised to bring a resounding end to the record-length snowless streaks a number of U.S. cities have notched this year. Blizzard warnings are posted over portions of Colorado, Nebraska, Kansas, Iowa, Illinois, and Wisconsin, and snowfall amounts of up to a foot are expected in some of the affected regions. While the heavy snow will create dangerous travel conditions, the .5" - 1.5" of melted water equivalent from the the storm will provide welcome moisture for drought-parched areas of the Midwest. Though much of the moisture will stay locked up as snow for the rest of the year, runoff from the storm may help keep Lake Michigan and Huron from setting an all-time record low for the month of December, and may also keep the Mississippi River at St. Louis above the -5' stage though the end of December. If the river falls below -5', barge traffic on the Mississippi may be forced to halt, costing billions of dollars. The Army Corps of Engineers is blasting away rocks on the river bottom south of St. Louis and releasing water from Carlyle Lake in Southern Illinois this week, in order to keep the Mississippi River high enough to allow barge traffic to negotiate the near-record low water levels. Several gauges on the Mississippi have set all-time record lows this year: the New Madrid, Missouri gauge on August 30, 2012 and the Tiptonville, Tennessee gauge on September 2. Records at the Tiptonville gauge go back to at least 1879.


Figure 1. Predicted precipitation totals fopr the 3-day period ending on December 22. Approximately 0.5 - 1.5" of melted water equivalent from Winter Storm Draco is expected over much of the drought-stricken Midwest. Image credit: NOAA/HPC.


Figure 2. Average water levels on Lake Michigan and Lake Huron are near their lowest December levels ever recorded, preliminary data from NOAA's Great Lakes Environmental Research Laboratory indicate.

Record snowless streaks coming to end because of Winter Storm Draco
The U.S. has had its warmest and 12th driest year on record, according to NOAA's National Climatic Data Center. It should be no surprise, then, that a number of major cities have set records for their longest period without snow. Most of these streaks have come to and end (or will do so in the next day or two) because of Winter Storm Draco:

MIlwaukee, Wisconsin's record streak without measurable snow ended December 18 with 0.5" of snow; the streak was 288 consecutive days, bookended by measurable snowfall on March 5 and Dec. 18. Milwaukee is likely to get an additional 4 - 6" of snow from Draco.

Omaha, Nebraska's record streak without measurable snow ended December 16 with 0.6" of snow; the streak was 295 consecutive days, bookended by measurable snowfall on Feb. 24 and Dec. 16. Omaha is likely to get 6 - 9" of total snow before the current storm winds down. Record latest first snow of the season: December 26, 1888.

Chicago, Illinois' new record snowless streak continues at 289 consecutive days as of Tuesday. The last measurable snow there was March 4. Previous record: 280 consecutive days between the measurable snowfalls of March 1, 1994 and December 5, 1994. Chicago has also broken its record for latest snowfall in the season, previously set on December 16, 1965. These streaks will likely end on Thursday, when 1 - 4" of snow are expected.

Rockford, Illinois' new record snowless streak continues at 289 consecutive days as of Tuesday, but this streak will likely end on Thursday, when 3 - 6" of snow are expected. The last measurable snow in Rockford was March 4. Previous record: 286 consecutive days between the measurable snowfalls of March 3, 1922 and December 13, 1922. Record latest first snow of the season: January 7, 1940.

Lincoln, Nebraska's new record snowless streak continues at 308 consecutive days as of Tuesday. This streak will likely end Wednesday or Thursday, as 6 -8" of snow are expected. The last measurable snow there was Feb. 13. Previous record: 295 consecutive days between the measurable snowfalls of Feb. 6 and Nov. 28, 2004. Record latest first snow of the season: December 31, 2006.

Syracuse, NY is often the snowiest major city in the contiguous U.S. This year, Syracuse has not yet had a 1" snowfall--the second latest such streak. The 3.0" that has fallen is over 28" below what Syracuse usually gets by this time of the season. The latest in the season that the first 1" snow has come to Syracuse occurred on December 22, 1998 (the previous warmest year on record in the U.S.) With the forecast calling for lake effect snows on the 22nd, Syracuse may just miss setting its mark for latest 1" snowfall of the season.

Jeff Masters

Winter Weather Drought Draco

November 2012: Earth's 333rd consecutive warmer-than-average month

By: JeffMasters, 2:57 PM GMT on December 18, 2012

November 2012 was the globe's 5th warmest November on record, said National Oceanic and Atmospheric Administration's National Climatic Data Center (NCDC) on Monday. NASA rated November 2012 the 2nd warmest November on record. Global temperature records begin in 1880. November 2012 global land temperatures were the 6th warmest on record, and global ocean temperatures were also the 6th warmest on record. Including this November, the 10 warmest Novembers have occurred in the past 12 years, and November 2012 was the 333rd consecutive month with global temperatures warmer than the 20th century average. The last time Earth had a below-average November global temperature was in 1976, and the last below-average month of any kind was February 1985--during the Reagan administration, when the cost of a first-class stamp was 20 cents. Global satellite-measured temperatures in November 2012 for the lowest 8 km of the atmosphere were 11th or 3rd warmest in the 34-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH), respectively. The September - October - November season of 2012 (fall in the Northern Hemisphere, spring in the Southern Hemisphere) was the globe's second warmest such period on record, behind 2005. The Northern Hemisphere snow cover extent during November 2012 was the fifth largest on record for the month, and marked the fourth consecutive November with above-average snow cover for the hemisphere. Wunderground's weather historian, Christopher C. Burt, has a comprehensive post on the notable weather events of November 2012 in his November 2012 Global Weather Extremes Summary.


Figure 1. Departure of temperature from average for November 2012, the 5th warmest November for the globe since record keeping began in 1880. The most unusual warmth was observed across parts of far eastern Russia, where temperatures were at least 5°C (9°F) above average for the month. Much warmer-than-average November temperatures, and even record warmth in several regions, were observed across the western United States, Mexico, Central and South America, eastern Russia, southeastern and western Asia, Australia, and most of Africa and Europe. Due to the near universal warmth in the Southern Hemisphere (with the exception of New Zealand), that region of the world observed its warmest November on record. In the Northern Hemisphere, cooler-than-average temperatures occurred across parts of central Asia, part of the eastern United States, and much of Alaska and western Canada. Nonetheless, the Northern Hemisphere land surface temperature ranked as the eighth warmest on record for November. Image credit: National Climatic Data Center (NCDC) .

Neutral El Niño conditions in the Pacific
Neutral El Niño conditions exist in the equatorial Pacific, where sea surface temperatures were 0.1°C below average as of December 17. NOAA's Climate Prediction Center (CPC) expects neutral El Niño conditions to last through winter and into early spring. Temperatures in the equatorial Eastern Pacific need to be 0.5°C above average or warmer to be considered an El Niño.


Figure 2. Arctic sea ice extent in November 2012 was the third lowest since satellite records began in 1979. Image credit: National Snow and Ice Data Center (NSIDC).

Arctic sea ice falls to 3rd lowest November extent on record
Arctic sea ice extent during November reached its third lowest extent in the 35-year satellite record, according to the National Snow and Ice Data Center (NSIDC). Only the November sea ice extents in 2006 and 2010 were smaller. This was the 19th consecutive November and 138th consecutive month with below-average Arctic sea ice extent. I discussed this year's extraordinary loss of Arctic sea ice in my November 20, 2012 post, Earth's attic is on fire: Arctic sea ice bottoms out at a new record low.

A new weather station deal
Owning your own backyard weather station that can upload the data to wunderground is great, but does come with its hassles---one of them being the fact that you always need to leave your Internet-connected computer powered up. However, RainWise, Inc. has created a new plug & play weather station system that links directly to wunderground.com without the need to route the data through your computer. RainWise is offering a package to our users that includes a wireless, solar powered MK-lll-LR weather station and compact IP-100 Internet gateway which come fully assembled for quick and easy installation. The system is Rapid Fire enabled with a refresh rate of just 3 seconds, so you can upload your weather data directly to us without having to utilize a computer source. RainWise is offering this package at a discounted price of $999.99. For more information or to purchase the PWS, click here.

Jeff Masters

Climate Summaries

A grinch in paradise: Category 4 Tropical Cyclone Evan slams Fiji

By: JeffMasters, 4:17 PM GMT on December 17, 2012

Mighty Category 4 Tropical Cyclone Evan walloped Fiji with sustained winds of 135 mph, torrential rains, and a dangerous storm surge on Sunday. Evan intensified markedly from a Category 3 storm with 115 mph winds to a Category 4 with 135 mph winds as it approached Fiji, and Evan's southern eyewall--the most intense part of the storm--brought hurricane conditions to a long stretch of the north and west coasts of Fiji's main island, Viti Levu. Preliminary media reports indicate that damage is very heavy on Fiji, but no lives have been lost. According to a database maintained by NOAA's Coastal Service Center, Evan is the strongest tropical cyclone on record to affect Fiji's main island, with records going back to 1941. The tourist town of Nadi on the northwest coast experienced sustained winds of 69 mph, gusting to 104 mph during Evan's passage, but did not experience the calm of the eye. Several smaller islands with popular surf resorts just offshore from Nadi did experience a direct hit, and damage is undoubtedly very severe on those islands. Evan is now over colder waters with higher wind shear, and satellite loops show a deterioration of the cloud pattern. Evan is expected to weaken below hurricane strength and transition to an extratropical storm before reaching New Zealand on Thursday. The most devastating cyclone to affect Fiji in recent decades was Category 2 Cyclone Kina, which killed 23 people and did $100 million in damage in January 1993. The only deadlier storm was Category 3 Cyclone Eric of 1985, which made a direct hit on the capital of Suva and killed 25.


Figure 1. Radar image from the Fiji weather service showing the large eye of Tropical Cyclone Evan just north of Fiji at 2:50 pm local time (02:50 UTC) on Monday, December 17, 2012. At the time, the city of Nadi was in the southern eyewall of Evan, and recorded sustained winds of 52 mph, gusting to 104 mph. Sustained winds at Nadi increased to 69 mph three hours later.


Figure 2. Tracks of all Category 1 and stronger tropical cyclones to pass within 100 miles of Fiji's main island of Viti Levu since 1941. Evan is the strongest cyclone on record to pass so close to the main island of Fiji. Image credit: NOAA's Coastal Service Center.

Severe damage in Samoa from Evan
Evan made landfall on the north shore of Samoa near the capital of Apia on Thursday as a Category 1 cyclone with 90 mph winds, and intensified into a Category 3 storm with 115 mph winds after the eye wandered back offshore late Thursday. Media reports indicate that Evan killed four and has left eight missing on Samoa, with 4,000 homeless. The main power plant for Samoa was destroyed, and it is expected that power will be out to almost all of Samoa for at least ten more days. Evan was one of Samoa's most destructive tropical cyclones on record, as discussed by wunderground's weather historian, Christopher C. Burt. After devastating Samoa, Evan smashed through the French territorial islands of Wallis and Futuna, causing major damage but no deaths or injuries.


Figure 3. Residents affected by Typhoon Bopha crowd as relief goods are distributed at New Bataan township, Compostela Valley, in the southern Philippines, Sunday Dec. 9, 2012. (AP Photo/Bullit Marquez)

Death toll from Super Typhoon Bopha rises above 1,000
In the Philippines, officials are still tallying the dead from deadly Super Typhoon Bopha, locally known as Pablo, which made landfall three times as it passed through northern Mindanao, central Visayas, and Palawan on December 4. The typhoon is now being blamed for at least 1020 deaths, making it the deadliest storm on the planet during 2012. At least 844 people are still missing and presumed dead. Bopha affected over 5.4 million people and left over 700,000 people homeless.

Jeff Masters

Hurricane

Category 3 Tropical Cyclone Evan bearing down on Fiji

By: JeffMasters, 5:19 PM GMT on December 16, 2012

Category 3 Tropical Cyclone Evan is closing in on the main island of Fiji, where hurricane warnings are flying and torrential rains are already falling. Radar images from Fiji show that the large eye of Evan is just north of the two main islands of Fiji. The expected southwesterly track of the storm should keep the calm of the eye just north of Fiji, though the southern eyewall may brush the north coast of the main island of Vici Leva, affecting the tourist town of Nadi. Evan has intensified today to its strongest level yet, with 120 mph winds, and satellite loops show that the storm remains well-organized, with plenty of intense heavy thunderstorm activity and a prominent eye. Evan will be in a region with moderate wind shear of 15 - 20 knots as it approaches Fiji, and could intensify by another 5 - 10 mph before making its closest pass to the islands later today. According to NOAA's Coastal Services Center, Evan is the strongest tropical cyclone to threaten Fiji since Tropical Cyclone Daman of December 2007. Dating back to 1972, twelve Category 3 or stronger tropical cyclones have threatened the Republic of Fiji.


Figure 1. Radar image from the Fiji weather service showing the large eye of Tropical Cyclone Evan just north of Fiji.

Severe damage in Samoa from Evan
Evan made landfall on the north shore of Samoa near the capital of Apia on Thursday as a Category 1 cyclone with 90 mph winds, and intensified into a Category 3 storm with 115 mph after the eye wandered back offshore late Thursday. Media reports indicate that Evan killed four and has left eight missing on Samoa, and left at least 4,000 homeless. The main power plant for Samoa was destroyed, and it is expected that power will be out to almost all of Samoa for at least ten more days. Evan was one of Samoa's most destructive tropical cyclones on record, as discussed by wunderground's weather historian, Christopher C. Burt.


Figure 2. True-color MODIS satellite image of Tropical Cyclone Evan nearing Fiji at 01:35 UTC December 16, 2012. At the time, Evan was a Category 3 storm with 115 mph winds. Image credit: NASA.

Jeff Masters

Hurricane

Category 3 Cyclone Evan leaves Samoa, heads for Fiji

By: JeffMasters, 3:06 PM GMT on December 14, 2012

Category 3 Tropical Cyclone Evan is finally done pounding Samoa and American Samoa, after spending two days meandering over the islands. Evan made landfall on the north shore of Samoa near the capital of Apia on Thursday as a Category 1 cyclone with 90 mph winds, and intensified into a Category 3 storm with 115 mph winds after the eye wandered back offshore late Thursday. Media reports indicate that Evan has killed two and brought heavy damage to Samoa. "Power is off for the whole country... Tanugamanono power plant is completely destroyed and we might not have power for at least two weeks," the Disaster Management Office (DMO) said in a statement. Satellite loops show a well-organized storm with plenty of intense heavy thunderstorm activity. The storm will be a region with light wind shear of 10 - 15 knots and very warm ocean waters that extend to great depth, and could intensify into a Category 4 cyclone by Saturday, as it passes through the Wallis and Futuna Islands. On Sunday, Evan is expected to pass just north of Fiji. The GFS model shows that Fiji should experience heavy rains from Evan, but miss the core eyewall region with the strongest winds and highest storm surge. The storm will encounter decreasing ocean heat content on Monday, after it passes Fiji, and should weaken to a Category 1 cyclone. Evan is one of Samoa's most destructive tropical cyclones on record, as discussed by wunderground's weather historian, Christopher C. Burt. The most famous and deadliest tropical storm to strike Samoa (in modern records) was that of March 1889, which influenced the balance of Western imperial power in the Southern Pacific.


Figure 1. People walk over a destroyed bridge in Samoa's capital Apia, Friday, Dec. 14, 2012, after cyclone Evan ripped through the South Pacific island nation. Phone lines, Internet service and electricity were down across the country, and the airport was closed. (AP Photo/Seti Afoa.)


Figure 2. The German corvette ‘Olga’ lies beached on Samoa following the cyclone of 1889. Photographer unknown.

Jeff Masters

Hurricane

Category 2 Evan batters Samoa, killing two

By: JeffMasters, 3:30 PM GMT on December 13, 2012

The Southern Hemisphere tropical cyclone season is beginning to heat up. Category 2 Tropical Cyclone Evan is pounding Samoa and American Samoa with heavy rains and high winds, after making landfall earlier today on the north shore of Samoa near the capital of Apia. At landfall, Evan had a small 10-mile diameter eye and top winds of 90 mph, but has since intensified to 105 mph winds. Media reports indicate that Evan has killed two, and brought a 12 - 15' storm surge, heavy rains, and severe damage to the island nation. Satellite loops show a well-organized storm with a tiny 7-mile diameter eye. Evan has plenty of intense heavy thunderstorm activity near its core, solid upper-level outflow, and is in an area with weak steering currents. Evan is expected to meander over Samoa until about 18 UTC on Friday, when a ridge of high pressure will build in and force the cyclone to the west. The storm will be in a region with light wind shear and very warm ocean waters that extend to great depth, and could intensify into a Category 3 or 4 cyclone by this weekend. On Sunday, when the ECMWF model predicts that Evan will be near Fiji, the storm will encounter increasing wind shear and should weaken.


Figure 1. True-color MODIS satellite image of Tropical Cyclone Evan over Samoa at 01:05 UTC December 13, 2012. At the time, Evan was a Category 1 storm with 90 mph winds. Image credit: NASA.

Jeff Masters

Hurricane

From the Lee Side: Penn State's Lee Grenci now a featured wunderblogger

By: JeffMasters, 6:24 PM GMT on December 12, 2012

"From the Lee Side" is the blog of wunderground's newest featured blogger--Lee Grenci. Lee put up his first post today, an educational piece on "Arctic Air Masses." He did an earlier guest post in Angela's blog, "The science of Sandy's transition", on whether or not Sandy was a hurricane at landfall (it wasn't.) Lee resides in Pennsylvania, and just retired as senior lecturer in Meteorology at Penn State University, where he was the lead faculty member for their online certificate in weather forecasting. I've been enjoying Lee's writings for many years in Weatherwise magazine, where he is a frequent contributor. Welcome, Lee!

While I'm on the subject of featured bloggers, I want to draw attention to the latest post by TWC's Stu Ostro, "Reflections on a surreal superstorm and the 2012 hurricane season". He discusses NHC's decision not to issue Hurricane Warnings for Sandy, as well as how climate change may have influenced the storm. TWC's Bryan Norcross has also posted his take on NHC's decision not to post hurricane warnings for Sandy.

Jeff Masters

Winter Weather

Dallas beats Chicago for first snow of the season; record snowless streak in Chicago

By: JeffMasters, 4:23 PM GMT on December 11, 2012

It's been a bad year for building snowmen in Chicago. It last snowed in Chicago on March 4, 2012, and Chicago has now gone 281 days in a row without snow, its longest such streak on record. Weather records for Chicago date back to 1871. Dallas, Texas had its first snow of the season yesterday, picking up 0.1". This is only the second time on record that Dallas has had an earlier first snow than Chicago. The only other time this has happened was in 1951, when Dallas received 0.6" on November 2, and Chicago had 4.4" on November 3.

With accumulating snow looking highly unlikely through at least December 14, Chicago's record for latest accumulating snow of the season may also fall. The average date for Chicago's first measurable snowfall is November 16, and the latest first snow of the season on record occurred on December 16, 1965. Rain mixed with snow is expected this weekend on the 15th and 16th, but the precipitation may fall entirely as rain. The lack of snow in Chicago this year is reflective of both how warm and dry it's been. The 25.20" of rain Chicago has received so far in 2012 is more than 10" below average, and the city experienced its 10th driest January - November period on record. Record warmth in early December brought Chicago only its 3rd 70°F December day on December 3.

Jeff Masters

Winter Weather

Hurricane Sandy was not an extreme Black Swan hurricane

By: JeffMasters, 3:47 PM GMT on December 10, 2012

I was in San Francisco last week for the annual Fall Meeting of the American Geophysical Union (AGU), the world's largest gathering of Earth Scientists. Over twenty thousand scientists from all over the world, including many of the world's top climate scientists and hurricane scientists, were in town to exchange ideas to advance the cause of Earth Science. One of the more intriguing talks was given by Ning Lin, a professor at Princeton University. She and Dr. Kerry Emanuel of MIT are studying "Black Swans"--tropical cyclones that are a surprise to the observer, and cannot be anticipated based on the 162-year historical record. Very rare extreme hurricanes that one might expect to occur naturally once every 10,000 years are possible, and “climate change has increased the probability of such storms,” Emanuel said at a press conference last week. In terms of storm surge, Sandy was not a black swan, since the 1821 hurricane that hit New York City had a higher storm surge. Historical records recount that the water rose thirteen feet in one hour at The Battery on Manhattan during the 1821 hurricane. The water level did not rise as high as during Sandy, though, since the 1821 hurricane hit at low tide.

Lin and Emanuel used a climate model in combination with a detailed hurricane model to generate a large number of hypothetical hurricanes in the future climate, and generated 10,000 years worth of storm surge events. They then used a detailed storm surge model (ADCIRC) to evaluate the storm surge risk these storms posed. Their three case studies:

1) The Persian Gulf. No tropical cyclones have ever been observed in the Persian Gulf, due to the Gulf's low humidity and high wind shear. However, the Gulf has some of the warmest water temperatures on the planet, and could theoretically support a strong tropical cyclone. The researchers' modeling predicted a 1-in-248,000 probability that a strong tropical cyclone originating in the western Persian Gulf could move eastwards and bring a 7 meter (16 foot) storm surge to Dubai in the United Arab Emirates. Obviously, such an event would be extremely disruptive to the global energy economy, which relies heavily on the infrastructure in the Persian Gulf.

2) Darwin, Australia. In 1974, tiny but powerful Tropical Cyclone Tracy brought a 1.6 meter (5.2') storm surge to the city. Lin and Emanuel's research showed that a black swam tropical cyclone with a probability of 1-in-70,000 is capable of bringing a devastating 11.5 meter (38') storm surge to the city.

3) Tampa Bay, Florida. Only two major Category 3 hurricanes have hit Tampa: an 1848 hurricane that raised waters levels by 4.6 meters (15'), and a 1921 storm with a storm surge of 3.2 meters (10.5'.) A black swan storm moving from south to north just offshore could set up a resonance in Tampa Bay and generate a 13 meter (43') storm surge. Such a storm has a 1-in-14,500 chance of occurring in a given year. This would likely do over $250 billion in damage, I expect.


Figure 1. Damage to Bayshore Boulevard after the 1921 Tampa Bay hurricane. The road leads to the Tampa Bay Convention Center from the south.


Figure 2. Track of the Tampa Bay Hurricane of 1921, one of only two major hurricanes ever to hit the city. This Category 3 storm with 115 mph winds brought a storm surge of 10.5 feet to Tampa Bay. A "Black Swan" hurricane capable of generating a 43' storm surge would not take a track like this, and instead would move from south to north just offshore.

Jeff Masters

Hurricane

Very warm November assures 2012 will be warmest year in U.S. history

By: JeffMasters, 4:39 PM GMT on December 07, 2012

The heat is on again in the U.S. After recording its first cooler-than-average month in sixteen months during October, the U.S. heated up considerably in November, notching its 20th warmest November since 1895, said NOAA's National Climatic Data Center (NCDC) in their latest State of the Climate report. The warm November virtually assures that 2012 will be the warmest year on record in the U.S. The year-to-date period of January - November has been by far the warmest such period on record for the contiguous U.S.--a remarkable 1.0°F above the previous record. During the 11-month period, 18 states were record warm and an additional 24 states were top ten warm. The December 2011 - November 2012 period was the warmest such 12-month period on record for the contiguous U.S., and the eight warmest 12-month periods since record keeping began in 1895 have all ended during 2012. December 2012 would have to be 1°F colder than our coldest December on record (set in 1983) to prevent the year 2012 from being the warmest in U.S. history. This is meteorologically impossible, given the recent December heat in the U.S. As wunderground's weather historian Christopher C. Burt reported, an early-December heat wave this week set records for warmest December temperature on record in seven states. December 2012 is on pace to be a top-20% warmest December on record in the U.S.

November 2012 was the 8th driest November on record for the U.S., and twenty-two states had top-ten driest Novembers. The area of the contiguous U.S. experiencing moderate-to-exceptional drought grew from 59% on November 6 to 62% on December 6. This is the largest area of the U.S. in drought since 1954.


Figure 1. Historical temperature ranking for the U.S. for November 2012. Arizona, Colorado, New Mexico, Utah, and Wyoming had top-ten warmest Novembers, while only North Carolina had a top-ten coldest November. Image credit: National Climatic Data Center (NCDC).


Figure 2. Historical temperature ranking for the U.S. for the January - November period. Eighteen states were record warm, and an additional 24 states were top ten warm. Image credit: National Climatic Data Center (NCDC).

Most extreme January - November period on record
The year-to-date January - November period was the most extreme on record in the contiguous U.S., according to NOAA's U.S. Climate Extremes Index (CEI), which tracks the percentage area of the contiguous U.S. experiencing top-10% and bottom-10% extremes in temperature, precipitation, and drought. The CEI was 46% in January - November, more than double the average of 20%. A record 86% of the contiguous U.S. had maximum temperatures that were in the warmest 10% historically during the first eleven months of 2012, and 71% of the U.S. of the U.S. had warm minimum temperatures in the top 10%--2nd highest on record. The percentage area of the U.S. experiencing top-10% drought conditions was 32%, which was the 4th greatest since 1910. Only droughts in the Dust Bowl year of 1934, and during 1954 and 1956, were more extreme for the January - November period. Heavy 1-day downpours have been below average so far in 2012, though, with 9% of nation experiencing a top-10% extreme, compared to the average of 10%.


Figure 3. NOAA's U.S. Climate Extremes Index (CEI) for January - November shows that 2012 had the most extreme first eleven months of the year on record, with 46% of the contiguous U.S. experiencing top-10% extreme weather-more than double the average of 20%.

Jeff Masters

Climate Summaries

At least 370 dead from Typhoon Bopha in the Philippines

By: JeffMasters, 5:21 PM GMT on December 05, 2012

The death toll in the Philippines from Typhoon Bopha has risen to at 370, with hundreds more missing. Bopha (called "Pablo" in the Philippines), slammed ashore on the Philippine island of Mindanao at 4:45 am local time on Tuesday morning as a Category 5 storm with 160 mph winds. Bopha is only Category 5 typhoon on record to make landfall on Mindanao, which rarely sees strong typhoons due to its position close to the Equator. Most of the deaths occurred in the gold-rush mountain towns of New Bataan and Monkayo due to typhoon-spawned landslides and flash floods. According to an op-ed published at sunstar.com, much of the death toll can be blamed on the fact that deforestation has reduced forest cover on Mindanao to just 10%, which allows more dangerous flash floods to occur. Passage over land has weakened Bopha to a Category 1 storm today, and the typhoon is now far enough from the Philippines that it no long poses a heavy rain threat. The island of Mindanao is highly vulnerable to flood disasters from tropical cyclones; last year's Tropical Storm Washi, which hit Mindanao on December 16, 2011 with 60 mph winds and torrential rains, killed over 1200 people. Before hitting the Philippines, Typhoon Bopha brought a storm surge estimated at ten feet to the island nation of Palau, where near-total destruction is being reported in some coastal areas.


Figure 1. Super Typhoon Bopha as seen from the International Space Station on December 2, 2012. At the time, Bopha had top sustained winds of 150 - 155 mph. Image credit: NASA.


Figure 2. The devastation brought about by powerful Typhoon Bopha is seen at Montevista township, Compostela Valley in southern Philippines Wednesday Dec. 5, 2012. (AP Photo/Bullit Marquez)

Extreme damage on Mindanao
Category 5 storms make landfall only once every few years somewhere in the world, and the damage they cause is invariably extreme and dramatic. According to a story at inquirer.net, a 10-hectare plantation of coconut trees in the town of Baganga, Davao Oriental, were all felled. It's takes some pretty extreme winds to bring down coconut trees, which commonly are the only things still standing after passage of a major hurricane or typhoon. Damage surveys from Tropical Cyclone Larry, which made landfall in 2006 in Australia as a Category 4 storm, indicated that coconut trees were able to withstand wind gusts of 135 mph, but toppled when the gusts reached 145 mph (thanks go to Dr. Bruce Buckley of the Reinsurance Group Australia for this info.) Aerial damage surveys from Mindanao (Video 1) show very heavy damage near where the eye came ashore, due to extreme winds and high storm surge.


Video 1. An aerial survey of damage near where the eye of Typhoon Bopha made landfall in Davao Oriental province on Mindanao Island in the Philippines shows widespread severe damage, bordering on catastrophic.

The International Red Cross is accepting donations for typhoon relief in the Philippines.

Jeff Masters

Hurricane

Typhoon Bopha hits the Philippines at Cat 5 strength; at least 40 killed

By: JeffMasters, 5:00 PM GMT on December 04, 2012

Typhoon Bopha slammed ashore on the Philippine island of Mindanao at 4:45 am local time on Tuesday morning as a Category 5 storm with 160 mph winds. Bopha is the third Category 5 typhoon to affect the Western Pacific this year, and the strongest typhoon ever recorded to hit Mindanao, which rarely sees strong typhoons due to its position close to the Equator. The death toll from the powerful storm already stands at 40, and is expected to rise. While passage over land has weakened Bopha to a Category 2 storm, the tropical cyclone is spreading torrential rains over a large portion of the southern Philippine Islands, and this will cause serious flooding problems today. The island of Mindanao is highly vulnerable to flood disasters from tropical cyclones; last year's Tropical Storm Washi, which hit Mindanao on December 16, 2011 with 60 mph winds and torrential rains, killed over 1500 people. Before hitting the Philippines, Typhoon Bopha brought a storm surge estimated at ten feet to the island nation of Palau, where near-total destruction is being reported in some coastal areas.


Figure 1. Super Typhoon Bopha as seen from the International Space Station on December 2, 2012. At the time, Bopha had top sustained winds of 150 - 155 mph. Image credit: NASA.

Bopha: the 2nd most southerly Category 5 typhoon on record
Bopha, a Cambodian word for flower or a girl, became a tropical depression unusually close to the Equator, at 3.6°N latitude. Tropical cyclones rarely form so close to the Equator, because they cannot leverage the Earth's rotation to get themselves spinning. Bopha became the second most southerly Category 5 typhoon on Monday at 7.4°N latitude. The record is held by Typhoon Louise of 1964, which was a Category 5 storm at 7.3°N.


Video 1. Scenes of wind damage and flooding from Typhoon Bopha's landfall in the Philippines yesterday.

Jeff Masters

Hurricane

Category 5 Super Typhoon Bopha bearing down on the Philippines

By: JeffMasters, 3:41 PM GMT on December 03, 2012

Extremely dangerous Typhoon Bopha is bearing down on the Philippine island of Mindanao as a Category 5 storm with 160 mph winds. Bopha completed an eyewall replacement cycle on Sunday and has been steadily intensifying today, and will make landfall on Mindanao in the early morning on Tuesday local time. Mindanao rarely gets hit by typhoons, since the island is too close to the Equator, and the infrastructure of Mindanao is not prepared to handle heavy typhoon rains as well as the more typhoon-prone northern islands. Bopha is potentially a catastrophic storm for Mindanao. The typhoon is following a similar track to last year's Tropical Storm Washi, which hit Mindanao on December 16, 2011 with 60 mph winds and torrential rains. Washi triggered devastating flooding that killed 1268 people. Washi was merely a tropical storm, and Bopha is likely to hit at Category 4 or 5 strength, making it the strongest typhoon ever recorded in Mindanao.


Figure 1. Super Typhoon Bopha at 01:45 UTC on December 2, 2012. At the time, Bopha had top sustained winds of 150 mph, as was just below its peak intensity of 155 mph, which it reached from 06 - 12 UTC on December 2. Image credit: NASA.

Bopha: the 2nd most southerly typhoon on record
Bopha became a tropical depression unusually close to the Equator, at 3.6°N latitude. Tropical cyclones rarely form so close to the Equator, because they cannot leverage the Earth's rotation to get themselves spinning. According to hurricane expert Dr. Paul Roundy of SUNY Albany, Bopha got its spin from a large-scale atmospheric wave called a mixed Rossby gravity wave. Because of the lack of atmospheric spin so close to the Equator, it took Bopha over four days to intensify into a typhoon, and it stayed a relatively small storm. Bopha became the 2nd most southerly typhoon ever recorded in the Western Pacific at 06 GMT on November 30, when the storm was at 3.8°N latitude. The Joint Typhoon Warning Center lists Typhoon Vamei of 2001 as the most southerly typhoon on record, at 1.5°N. However, other meteorological agencies do not credit Vamei with reaching typhoon strength, so this record is disputed. The previous most southerly typhoon was Typhoon Kate of 14 - 25 October 1970, which reached typhoon intensity at 4.3°N, 137.4°E. Bopha continued intensifying over the weekend, becoming the second most southerly super typhoon ever recorded (150 mph winds) at 00 GMT on December 1, when it was at 6.1°N latitude. The record most southerly super typhoon was Kate, which reached super typhoon intensity at 6.0°N, 126.3°E. Kate struck the Philippine island of Mindanao as a Category 4 storm, killing 631 people. Bopha further intensified into a Category 5 typhoon on Monday at 7.4°N latitude, becoming the second most southerly Category 5 typhoon on record, next to Typhoon Louise of 1964, which was a Category 5 storm at 7.3°N. According to NOAA's Coastal Services Center, there have been only 4 previous typhoons of at least Category 4 strength to track within 200 nautical miles of Mindanao Island, dating back to 1945: Mike ("Ruping" ) in 1990, Ike ("Nitang") in 1984, Kate ("Titang") in 1970, and Louise ("Ining" ) in 1964.


Figure 2. Tracks of all Category 4 typhoons to affect the southern Philippine Island of Mindanao since 1945. Image credit: NOAA Coastal Services Center.

The closest a tropical cyclone has ever been to the Equator is 0.7°N, by Tropical Cyclone Agni in the North Indian Ocean in November 2004. Agni got counter-clockwise spin from the presence of the summer monsoon circulation in the Indian Ocean. The closest a Western Pacific tropical cyclone has been to the Equator is 1.4°N latitude, by Tropical Storm Vamei on December 27, 2001. Vamei hit Singapore after Christmas in 2001, at a latitude of 1.5°N.


Figure 3. This MET-5 visible satellite image taken at 0400 UTC November 28, 2004, shows Agni as a developing tropical storm just north of the Equator in the Indian Ocean. Image credit: Navy Research Lab, Monterey.

Jeff Masters

Hurricane


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

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