May 3rd, 2011

Update: Severe Weather in Southern United States

Posted at 9:30 AM ET

severe-us-2-smallSevere weather in southern regions of the United States spawned hundreds of tornadoes on April 27, killing around 340 people in six states, damaging thousands of buildings and likely causing billions of dollars of insured losses, according to reports. The fatalities occurred in Alabama, Georgia, Mississippi, Tennessee, Virginia and Kentucky in what is being described as the second deadliest single day tornado outbreak in U.S. history, surpassed only by an event on March 18, 1925 which killed nearly 750 people. In terms of the human cost, the latest event is the worst natural disaster to hit the United States since Hurricane Katrina in 2005, when up to 1,800 people were killed. According to the National Weather Service (NWS), the event was the most severe 24-hour tornado outbreak ever in the United States as the more than 300 tornadoes were spawned between 08:00 EDT on April 27 and 08:00 on April 28 (the previous record was set on April 3-4, 1974 when 148 tornadoes were reported). The severe weather also brought strong winds, heavy rain and large hail to several communities. Reports said some tornado tracks were almost a mile wide and tens of miles long. Several states suffered power outages and widespread property and infrastructure damage has been reported.

Several storm systems battered states across southern regions of the United States during the second half of April, with severe weather being blamed for the deaths of 10 people in Arkansas and one in Mississippi early last week. Significant damage at Missouri’s Lambert-St Louis International Airport also occurred during this time. The NWS said it received preliminary reports of more than 600 tornadoes during April 2011 (the previous record number of tornadoes set during the month of April occurred in 1974 when 267 tornadoes were reported). Severe weather spawned around 200 tornadoes in 14 southeastern states between April 14 and 16, damaging hundreds of properties and killing at least 45 people. According to the NWS, tornado activity so far in 2011 is running at record pace, with the number of tornadoes for the year already at 881. Meteorologists said unseasonably warm temperatures in the Gulf of Mexico contributed to the high level of tornado activity, as the humidity combined with cooler temperatures and vertical wind shear to create a dangerous mix. May is historically the most active month for tornadoes.


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According to reports from state emergency management agencies, the bulk of the damage during the latest storms occurred in occurred in Alabama, Georgia, Mississippi and Tennessee. Reports said Alabama was worst hit as several communities were leveled. According to officials, 31 of the state’s 67 counties were affected by the tornadoes and storms (Autauga, Bibb, Blount, Calhoun, Cherokee, Choctaw, Cullman, DeKalb, Elmore, Etowah, Fayette, Franklin, Greene, Hale, Jackson, Jefferson, Lawrence, Limestone, Madison, Marengo, Marion, Marshall, Sumter, St. Clair, Tallapoosa, Tuscaloosa, Washington and Walker). President Barack Obama approved emergency aid for Alabama after more than 250 people were killed in 19 counties. Around 1 million people were left without power at the height of the storms, although this had been reduced to 400,000 households by May 1. The Alabama Power Company said the number of power outages rivaled those experienced after hurricanes Ivan and Katrina. The NWS said there had been preliminary reports of 66 tornadoes in Alabama alone, causing widespread damage and disruption. Northern and central regions of the state bore the brunt of the latest storms and Governor Robert Bentley said the severe weather left “major destruction” in the state.

The city of Tuscaloosa was one of the hardest-hit areas in Alabama after a tornado, reportedly one mile wide, swept across the city, leaving severe damage in its wake and killing at least 36 people. Almost 1,000 people were treated for injuries in the city and 446 people were unaccounted for, although not necessarily missing. Experts say the tornado in Tuscaloosa could have been an EF5, the strongest category of tornado. Officials said the damage was compounded by the earlier storms, which allowed the new system to uproot weakened trees. One meteorologist described the tornado that devastated Tuscaloosa as possibly the “worst in Alabama’s history”. Reports said debris littered the streets of Tuscaloosa, with dozens of roads impassable and hundreds of homes and businesses destroyed. Mayor Walter Maddox told reporters the city faced “massive damage on a scale we have not seen in Tuscaloosa in quite some time”.

Witnesses also reported tornado touchdowns in Jefferson County, home to Birmingham, Alabama’s largest city. Birmingham Mayor William Bell said the damage trail in the city was around a mile wide, with northwestern areas particularly badly hit. Several people have been reported missing in Birmingham and hundreds more were injured. Another nearby town, Hackleburg, was reported to be “90 percent destroyed” by a tornado with winds of up to 200 mph (320 kmph). Further north, the Browns Ferry nuclear power plant, located about 30 miles west of Huntsville, lost power and the three reactor units at the facility were automatically shut down during the storm. The Nuclear Regulatory Commission said the safety systems at the Tennessee Valley Authority-owned plant operated as needed and the emergency event was classified as the lowest of four levels. The plant is expected to be shut for days, possibly weeks, as workers repair damaged transmission lines. The tornadoes also badly hit Alabama’s poultry industry, with producers estimating that more than 2 million birds have been lost because of the storms, according to emergency management officials. Some commercial structures also sustained extensive damage, including several clothing and auto plants. The severe weather also halted coal production at the Cliffs Natural Resources mine in Alabama. About 2,000 National Guard soldiers have been deployed in Alabama to assist with rescue and clean-up operations.

Georgia was also badly hit by the severe weather, prompting Governor Nathan Deal to declare disaster areas in sixteen counties, including Catoosa, Floyd, Dade and Walker. According to the Georgia Emergency Management Agency, 15 people were killed in Georgia, with fatalities reported in Catoosa County, Dade County, Lamar County, Rabun County and Spalding County. Several Georgian counties reported damage from tornadoes and officials said the town of Ringgold in Catoosa County was hit particularly hard, with at least 300 homes lost. In Floyd County, emergency management officials said around 150 homes were damaged by the storms. Georgia Power reported that more than 50,000 people were left without power across the state.

Elsewhere, Mississippi, Tennessee and Virginia were also badly affected by the severe weather. Mississippi Governor Haley Barbour issued a state of emergency after 34 people were killed across the state. Damage was reported in 50 counties and authorities said an EF5 tornado caused severe damage in Smithville (Monroe County). President Obama has signed a disaster declaration for the Mississippi counties of Chickasaw, Choctaw, Clarke, Greene, Hinds, Jasper, Kemper, Lafayette, Neshoba, Monroe and Webster. Early damage assessments indicated around 1,000 homes were destroyed in the state with another 2,500 damaged. The NWS said it received more than 40 preliminary reports of tornado touch downs in Mississippi.

The severe weather also hit parts of Tennessee and Virginia. Officials in Tennessee said 34 people were killed in the state and more than 500 Tennessee homes were destroyed or sustained major damage. Governor Bill Haslam has asked President Obama to declare four counties (Bradley, Greene, Hamilton and Washington) federal disaster areas. In Virginia, an additional five victims were reported after 15 tornadoes moved across the state. Reports said storms affected several Virginia counties, including Goochland, Halifax, Shenandoah and Washington, with Washington and Halifax hardest hit. Officials say more than 425 structures were reported damaged from the tornadoes, including 55 structures that were destroyed and 77 that had major damage.

According to EQECAT, the severe weather is likely to have caused an insured loss of between USD2 billion and USD5 billion. EQECAT said its estimate is based in part on initial reports of nearly 10,000 buildings destroyed. The firm added that the severe weather was comparable to the Oklahoma City tornado outbreak in 1999 that caused USD1.6 billion in damage and the 2003 tornado outbreak in Kansas, Missouri, Arkansas and Oklahoma that caused an insured loss of USD4.5 billion.

Sources: BBC News, Agence France Presse, Associated Press, Reuters News, CNN News, EQECAT

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Guy Carpenter publishes CAT-i reports for major natural catastrophes worldwide. These reports cover catastrophes including worldwide tropical cyclones, earthquakes, major UK and European floods and any other natural event that is likely to incur a significant loss to the (re)insurance industry. Please email if you wish to be added to the free email distribution list.

Guy Carpenter compiles RISK-i reports for major technological or man-made events worldwide. These reports cover risks to property, transport and life including explosions, fires, crashes, engineering disasters and terrorist attacks that are likely to incur a significant loss to the (re)insurance industry. Please email if you wish to be added to the free email distribution list.

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