Top Ten U.S. Weather Events Of 2012


by Jeff Masters, via the Wunderblog

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.

Jeff Masters is the co-founder of the Weather Underground. This piece was originally published at the Wunderblog and was reprinted with permission.

20 Responses to Top Ten U.S. Weather Events Of 2012

  1. Mike Roddy says:

    Thanks for this, Jeff, and for all of your hard work.

    This summary should be on the network news.

  2. prokaryotes says:

    News like this make frontpage today:

    Stolen Dog Returned to Heartbroken Girl on Christmas

  3. John McCormick says:

    Take a few minutes to watch a fascinating video presented by Peter Sinclair and featuring Dr. Jennifer Francis and Jeff Masters. Together they make the weather weirding easier to understand by focusing on the Arctic ice melt back and its impact on the jet stream.

    This is one straightforward way to understand this hugely complex Northern Hemisphere weather system.


  4. Wonderful time-lapse treatment of the year’s weather. That must have taken a fair bit of work.

    Also, Larry Smit’s photo of the lava-lamp clouds was literally awesome (that is, it inspires awe). The tidy phalanxes of submerged cabs from Charles Sykes was also great. It looks like the sea pushing back on the invading forces–which, again, it literally is, albeit minus the implication of intention.

    The unusual jet stream flow, distorted by the shrinking ice cap, featured in many of the weather events. It was certainly prominent in Sandy, with a deep lobe plunging south across the Atlantic to deflect it 90 degrees west, and the non-winter of 2011-2012 including the eerie March heat wave in the northern-tier states.

  5. Ditto Mike on his thanks to Jeff. These overview articles are useful for researchers and advocates.

    And don’t worry, guys…pretty soon every news story will have climate as its subject or back story. Eg., “Little girl’s dog rescued from climate disaster.” Of course by then it will be too late to do much of anything about it. But at least we’ll get our 15,000 years of fame.

  6. prokaryotes says:

    There is better reporting since some time, but the media is still not connecting the dots on extreme weather and the science. Like the anomalies from a changed Jet Stream mode, because of less sea ice.

    2 Tornadoes in Mobile in 1 week, unusual temperature records etc etc. Instead you get now “let’s explore geoengineering as a fix”.

    But we need to reduce emissions and the best way is a carbon tax for this to work.

  7. Geo-engineering seems like remediating hubris with more hubris. Why it’s preferable to address a problem of complexity with more complexity is beyond me. The Law of Unintended Consequences casts a long, dark shadow down that road.

    We should stick with the Rule of Holes: if you’ve dug yourself too deep, the Step One is, stop digging.

    A carbon tax, as soon as possible. Also, restructure corporations to de-personify them, and reverse Citizens United. Corporations are not people, and money is not speech. That would lower resistance to a carbon tax.

  8. Turboblocke says:

    Who’s going to underwrite the risks of geo-engineering. IMO geo-engineering is going to make the lawyers very rich.

  9. Paul Klinkman says:

    Honorable mention for 2012: 15 tornadoes in Alabama — wait for it — on Christmas Day, 2012.

  10. Paul Klinkman says:

    Cutting fire lines to prevent future forest fires is geoengineering. If it’s your house on the other side of the fire line, it’s common sense geoengineering. If it reduces the carbon put into the atmosphere from megafires, it’s carbon-reducing geoengineering.

    Thousands of wind-powered snow-making machines in the tundra will enhance snowfall at strategic times, so that more sun gets reflected back into space the way it used to work pre-eaarth. That’s pretty environmentally benign geoengineering. I think that the government should take the risk, within limits.

  11. Paul,

    Thanks for introducing the concepts of scale and timing.

    The term “geo-engineering” conjures speculative, pre-emptive, planetary-scale efforts, like launching massive amounts of aerosols into the sky or “fertilizing” the ocean with huge discharges of iron oxide to encourage plankton growth.

    Absolutism is always suspect. I agree there may be some geo-engineering that makes sense, if the definition includes small-scale efforts like fighting fires or making snow from carbon-free machines. (Is there such a thing?)

    Even these, though, can have unintended effects. Long-term suppression of fires allowed fuel to build in our national parks, as evidenced by the great Yellowstone conflagration a few years ago. (Makes you wonder what to do about all those trees in the Rockies done in by the pine bark beetle.)

    But pre-emptive geo-engineering as the first-order solution to climate change strikes me as high-risk and liable to provoke perverse dynamics. Super-abundant natural gas should be a godsend because it’s far lower in carbon than coal and can easily be ramped up and down to support renewable generation. But perversely, it’s displacing renewables as well as coal, and the coal it’s displacing is going overseas.

    Without mandatory, concurrent, dramatic reductions in carbon output–a coordinated effort–large-scale, pre-emptive geo-engineering should be regarded warily.

    You may have seen this new group, the Arctic Methane Emergency Group. They presented some geo-engineering ideas at the recent American Geophysical Union meeting. I’ve just come across this myself, and am reading with interest. I’ve been saying it’s all about the ice cap for some time; these guys are REALLY saying that. Much to think about. I’m waiting fro the NSIDC or NASA to weigh in on their sense of urgency.

  12. Merrelyn Emery says:

    Shows you why the deniers are getting desperate, ME

  13. wili says:

    I guess it’s subsumed under the general topic of #2 “Warmest Year on Record,” but I think the anomalous ratios of high to low records, especially in March (32:1 iirc) and the first week in December (132:1 ! iirc) deserve some kind of special mention.

    Do we have an estimate for the overall ratio for 2012?

  14. Ozonator says:

    Deniers aka more self-proclaimed masters of weather forecasting and all science failed to predict even 1 itty bitty tornado. For example, “Dec 25, 2012 … The new robber barons … Paul Driessen”; “Dec 19, 2012 … Another snowjob from UNH and NRDC … By Joseph D’Aleo, CCM”; “Dec 25, 2012 … Kerry as Secretary of State: Global warming first, world hunger, disease, and nuclear arms second … By Steve Goreham”; “Dec 19, 2012 … New leak shows predictions of planetary warming have been overstated … Chilling climate-change news”; “Dec 20, 2012 … SOON AND MORNER: Sea-level rise data based on shoddy science … Willie Soon and Nils-Axel Morner”; “Dec 25, 2012 … Book review: Redressing global climate hysteria … Anthony Sadar”; and “Dec 14, 2012 … Severe 2012 U.S. Drought Not Caused By Human CO2, Confirms NOAA … C3 Headlines” (whistlesuckers perfuming the stink at Joey D’Aleo’s

  15. Paul Klinkman says:

    Super-abundant natural gas is the #1 villain in climate change, because natural gas is 100% methane. After it leaks out of “dry” fracked wells, cracks in pipelines and unlit pilot lights, methane acts as a greenhouse gas maybe 20 times more potent than carbon dioxide. It accelerates climate change right now. With our world’s positive feedback loop, right now acceleration from leaking methane can be deadlier to the climate than mining and burning an equivalent energy amount of coal or oil.

    I’m quite concerned that although forests capture carbon most years, most of the carbon eventually gets burned back into the atmosphere in a big fire. No professor, graduate student, undergraduate or high school science fair entrant in the U.S. deals with enhancing the ability of forests to sequester carbon long-term. So who out there wants to wake up and do the right thing?

    When I count to three and snap my fingers you will wake up and do the right thing. Will that work for you?

  16. Geoengineering. The problem with the government taking the risk is that corporations will make huge profits experimenting with the weather and the taxpayers will end up paying for the consequences, both intended and unintended. Since no one has a clue about what would work, those consequences would likely be quite dire if one of our fave Corps., say Haliburton, took to the skies.

    Carbon sequestration is a better option, but I have on good authority from some of the world’s leading experts that oceanic sequestration is at best a theoretical possibility and at worst a pipe dream. Biochar, however, has real possibilities and can be affordably scaled. One proposal is to take all those trees killed by the pine beetle and turn them into biochar, a carbon negative process.

  17. prokaryotes says:

    Updated with acute indications for mass extinction event.

  18. Lewis Cleverdon says:

    Philip – while I fully support the biochar option (in particular that of native coppice afforestation for biochar and coproduct methanol) I’d also warn that it could be done extremely badly, to the point of being ruinously counterproductive. Consider the evictions worldwide of subsistence farmers, and the clearance of old-growth forests, for corporate profiteering in the form of immense monoculture GMO tree plantations supplying biochar to global agribusiness, with the carbon credits sold as ‘offsets’ for continued industrial pollution.
    – And then as famine bites and the evicted destitute peasantry in city shanty towns riot, govt’s are overthrown, global agreements are torn up and the plantations burn . . . .

    From this outlook what matters with both modes of geo-e is the quality of global governance under which they’re applied. And unless Americans would tolerate Chinese influence over US weather, that governance will have to be global – in the form of a United Nations supervision agency accountable to the member nations. That agency’s scientists would oversee the accreditation of options’ objectives, research and scaled trials, with the mandate to deploy any particular option being a decision of the member nations.

    The Albedo Restoration mode has a huge and irrational prejudice now obstructing its research, when it could potentially be done as well as the best approaches to biochar, and it offers the critical benefit of rapid effect – global temperature could be lowered within two to three years of full deployment (according to Professor Salter, who researches the ‘Cloud Brightening’ option).

    By contrast, even discounting the feedbacks, Emissions Control alone would only halt further warming 30yrs after we ended emissions (i.e. leveling off by 2080 after a 2050 near-zero-output target). And the best Carbon Recovery scenario via biochar that I’ve seen would potentially cleanse the atmosphere by 2100, giving a 2130 date for the cooling to be fully realized. While both these mitigation tactics are plainly necessary, even if they’re applied with radical urgency they are obviously not sufficient to have any notable cooling effect within 40 or 50 years, and the probability of ruinous global crop failures within 10 or 15 years is now rising fast.

    In short, Albedo Restoration is now essential to lower global temperature and stabilize climate, and also to halt the further acceleration of the interactive feedbacks, during the many decades of steady effort needed to end GHG emissions and cleanse the atmosphere. Without that stabilizing effect, there is scant prospect of the global economy affording the investment in either emissions control or carbon recovery. Consider: total US weather damages in 2012 seem likely to match most of its growth of GDP, this early in the curve of global warming.

    The way out of the hole we’re in is certainly to stop digging (up fossil carbon as fuel) and to build ourselves a ladder, whose rungs are ppm of carbon recovered, and whose rails are the pre-industrial temperature achieved by Albedo Restoration.

    If there are any other plausible options to halt the feedbacks and stabilize global climate for the many decades needed for Emissions Control and Carbon Recovery to take effect, I’d like to hear them.