Monster Alabama Tornado Spawned by Rare "Perfect Storm"
U.S. southern tornados become second-deadliest in history
Photo taken on April 28, 2011 show the destroyed houses and cars in Tuscaloosa, Alabama, the United States. (Xinhua/Song Qiong)
WASHINGTON, April 30 (Xinhua) -- The death toll from the devastating tornados that swept through the southern United States this week has risen to at least 342, making it the second-deadliest tornado outbreak in American history.
By early Saturday morning, emergency management officials tallied 254 deaths in Alabama, 34 in Tennessee, 33 in Mississippi, 15 in Georgia, 5 in Virginia and 1 in Arkansas, the CNN reported.
This is the deadliest tornado outbreak since March 1932, when 332 people were killed. The death toll is also the second-largest in the country's history, only below that of a 1925 tornado outbreak which left 747 people dead, according to the National Weather Service.
In the hardest-hit Alamba, the confirmed fatalities have soared to 254, according to the state Emergency Management Agency. In addition, more than 1,700 people were injured while several others still missing.
U.S. President Barack Obama on Friday flew to Tuscaloosa, Alabama. The city, with a population of over 90,000, has lost at least 45 lives in the storms and tornados.
Clash of warm, cold air encouraged "history making" tornadoes.
Buildings in Tuscaloosa, Alabama, lie in ruins on April 28, a day after a tornado demolished the city.
Those conditions—which stretched across Mississippi, Alabama, andGeorgia—included warm, moist air rising and mixing with colder, dry air at higher altitudes.
Unfortunately for those living in the tornadoes' path, "weather conditions came together perfectly," said Tim Samaras, a Denver, Colorado-based tornado expert and producer of the tornado-research website TWISTEX.
"Mississippi, Alabama, and Georgia had that down to a T. It was a very, very rare day for everything to come together for this type of event," said Samaras, also aNational Geographic Society Emerging Explorer. (The Society owns National Geographic News.)
Upper-level winds known as the jet stream also caused the storm system to rotate, according to meteorologist Jeff Masters, director of the website Weather Underground.
Rotating thunderstorms—known as super cells—spawn tornadoes. In the South on Wednesday, such storms spawned an outburst of a hundred or more twisters, which barreled through six states and killed at least 283 people.
"This is a history-making tornado outbreak," Masters said. "You don't see many like this."
Tuscaloosa Tornado Shattered Record?
The mile-wide (1.6-kilometer-wide) Tuscaloosa tornado may have had winds exceeding 260 miles an hour (418 kilometers an hour), which would make it an F5 storm on the Fujita scale. The scale ranks tornadoes from F1 to F5 based on wind speeds and destructive potential.
Investigators are trying to determine how long the tornado, which originated just southwest of Tuscaloosa, stayed on the ground.
Tornadoes usually touch the ground for only a few miles before they dissipate. But favorable meteorological conditions may have sustained the Tuscaloosa twister for a record-breaking trek of 300 miles (482 kilometers) across Alabama and Georgia. (See more tornado pictures.)
"There were no limitations," said tornado chaser Samaras. "It went absolutely crazy. It had nothing but hundreds of miles to grow and develop."
The current record for a tornado's ground time is three and a half hours, set in 1925 by a twister that killed 747 people as it moved 219 miles (352 kilometers) across Missouri and Illinois before falling apart in Indiana.
This year's stormy April marks only the beginning of the tornado season, which continues through June, experts say.
Samaras noted that twisters usually move northward as the season progresses. Oklahoma, Kansas, and Nebraska typically see tornadoes in May, while in June the funnels form in Minnesota and parts of the Dakotas.
"We still have two very busy months left," Weather Underground's Masters cautioned.