News•January 31, 2013

Deadly Georgia Tornado First in a Record 220 Days

The longest streak of days on record without a tornado-related fatality in the U.S. came to a violent end on Wednesday morning, when a large and powerful tornado struck Adairsville, Ga., killing at least one person in a mobile home park. That tornado, which may rank as an EF-4 — the second most powerful on the Enhanced Fujita Scale — overturned cars on I-75 and damaged numerous buildings in downtown Adairsville, which is about 60 miles northwest of Atlanta. Other twisters touched down in Arkansas, Illinois, Indiana, Missouri, Mississippi, Oklahoma, and Tennessee. At least one other death is being blamed on the severe weather, after high winds killed a Nashville resident by knocking a tree down onto the shed where he was living, according to WSMV-TV.

Severe weather reports for Jan. 30, showing hail/wind reports in blue, and tornado reports in red.
Credit: NWS/SPC.

The tornadoes were part of a three-day outbreak of severe weather associated with a sprawling storm system that brought spring-like temperatures and humidity to the Midwest and East Coast, along with howling winds on Wednesday night into Thursday. Winds gusted as high as 81 mph in Massachusetts, and topped 60 mph in New York City, where scattered power outages and damage occurred. Sustained winds were clucked at close to 50 mph in Southern New England, disrupting air travel at numerous major airports.

Until the Adairsville tornado, the U.S. had gone 220 days without a tornado death. The last tornado death was in Highland County, Fla., on June 24, 2012. The previous record was 197 days, which occurred between August 1986 and February 1987. Reliable tornado records extend back to 1950, according to the Storm Prediction Center in Norman, Okla., which is part of the National Oceanic and Atmospheric Administration.

The record streak was largely a consequence of the low number of tornadoes that the U.S. saw during 2012, and the fact that the strongest tornadoes that did occur tended to miss heavily populated areas. Because tornadoes require a particular combination of ingredients in order to form, the number of tornadoes is highly dependent on the prevailing weather patterns, and tornado statistics tend to fluctuate considerably from one year to the next.

During 2012, the same weather pattern associated with the record heat and drought also stifled tornado activity by keeping a very hot, dry, and stable air mass in place across Tornado Alley. The heart of Tornado Alley was where the drought was most intense. For example, Nebraska had its driest year on record last year, and extreme drought conditions were present in Oklahoma, Missouri, Iowa, and other states where spring and summer twisters are typical. While natural climate variability likely played a major role in initiating the drought, climate scientists said global warming may have made the drought worse by making conditions hotter, and therefore drier, than they otherwise might have been.

Video of the Adairsville tornado. Credit: hi5viralnews5/Youtube. NOTE: Language is NSFW.

The total number of tornadoes during 2012 was 936, and the last time there were fewer than 1,000 observed tornadoes in a single season was in 2002. July of 2012 saw the fewest number of tornadoes since modern records began in 1954, with more tornadoes occurring in Canada than in the U.S., which is unusual.

The storm system responsible for the Adairsville tornado brought a wide range of other hazards as well, from damaging wind gusts to record rainfall and flash flooding. According to meteorologist Jeff Masters of Weather Underground, three northern upper-air weather stations, including Caribou, Maine near the Canadian border, set all-time records for January moisture, as the storm pumped warm, humid air from the Gulf of Mexico northward. In the nation's capital, the unusually high atmospheric moisture content led to 2 to 6 inches of rainfall, which caused widespread flash flooding problems.

Just days after record cold gripped the region, the East experienced a spring preview on Wednesday, and many locations in the Midwest, Mid-Atlantic, and Northeast set daily high temperature and precipitation records.

Washington Dulles Airport hit 72°F, which beat the record of 70°F, and set a record-warm daily low temperature, with an overnight low of 56°F. Other record highs were set in Wilmington, Del., Buffalo, Newark, N.J., and Worcester, Mass. On the summit of Mount Washington, N.H., located at an elevation of 6,288 feet above sea level, Wednesday's high temperature of 43°F broke the previous record of 38°F, set in 1947. According to the Mount Washington Observatory, the record high was broken again on Thursday, when the temperature hit 38°F shortly after midnight. It's rare for temperatures to exceed the freezing mark during January at that location, which is well-known for its harsh winter weather. On Jan. 23, for example, the high temperature on the summit was minus 26°F.

According to NOAA's National Climatic Data Center, there were 278 record daily high temperatures set or tied on Jan. 30 along with 163 record-warm overnight low temeratures, compared to only nine record daily cold high temperatures set or tied, and zero record cold overnight lows. During January, warm temperature records outpaced cold temperature records despite the waves of exceedingly cold Arctic air that affected much of the northern Plains, Midwest, and East.

As the climate has warmed during the past several decades, there has been a growing imbalance between record daily high temperatures in the contiguous U.S. and record daily lows. A study published in 2009 found that rather than a 1-to-1 ratio, as would be expected if the climate were not warming, the ratio has been closer to 2-to-1 in favor of warm temperature records during the past decade (2000-2009). This finding cannot be explained by natural climate variability alone, the study found, and is instead consistent with global warming.