At least 117 deaths were attributed to the Missouri storm late Tuesday, making it the nation’s deadliest single tornado in recorded history. Roughly 2,000 buildings were destroyed in the city, FEMA reported.
The Joplin storm was the second historic tornado outbreak to hit the nation, coming less than a month after hundreds of tornadoes ripped across the South in April, killing 238 people in Alabama, including nine in Calhoun County. Re-cord-setting severe weather hasn’t been limited to tornadoes. The Mississippi River slowly swelled to record levels over the past weeks, forcing towns along the waterway to evacuate and causing damage estimated in the billions.
“It’s been a fairly active year. Above average, no doubt about it,” said Scott Unger, meteorologist with the National Weather Service in Birmingham.
Alabama has seen 108 tornadoes so far in 2011, topping the previous record of 94 in 2008, according to the National Weather Service. April 27 saw a single-day-record 63 tornadoes sweep across the state, Unger said.
Many of those tornadoes were unusually strong, with two EF-5 twisters -– with winds above 200 mph –- striking the northwestern part of the state, data released by the weather agency show.
Seven EF-4 tornadoes -– with winds blowing between 166 and 200 mph –- tore across the state that day, according to the National Weather Service.
All told, there have been more EF-4 and EF-5 tornadoes in 2011 than in the entire preceding decade.
It’s unclear why this year has seen so many powerful tornadoes. But a contributing factor to the twisters pulverizing Southern cities rather than fields across the central plains can be attributed to the fact that 2011 is a La Nina year, said John Christy, Alabama’s state climatologist.
Water temperatures drop in the eastern Pacific and rise in the western Pacific, affecting air circulation for the entire planet, Christy said. This temperature shift occurs every three to five years and lasts for about five months.
Shifting ocean temperatures push the normally meandering North American jet stream south and east. The stream flows along the northern side of a Texas ridge, comes down the east side of the state and troughs through Mississippi and the mid-South, funneling up the Ohio Valley, Christy said.
“Tornado alley sort of moves to our direction during La Nina,” Christy said, noting that the historic 1974 tornado outbreak was also a La Nina year.
But while there was a higher probability of tornadoes hitting the South this year, there was no way to predict the strength of this year’s La Nina pattern or how powerful this spring’s tornadoes were, Christy said.
Whether climate change increased the amount of available moisture and warm air pulled off the Gulf of Mexico contributed to storm strength this year is also unknown, said Jody Aaron, meteorologist with the National Weather Service. More research on the topic is needed before a conclusion can be drawn, he said.
There is no relation to increasing carbon dioxide and tornadoes, Christy wrote in an email, noting that the trend since 1950 is downward. It was just a bad year for tornadoes, he wrote.
“This was a remarkable outbreak. You’re not going to see an outbreak like this every La Nina,” Christy said.
However, the larger pattern of drought in Texas and south Alabama –- as well as floods in the Ohio River Valley and the Mississippi River –- tend to be related to the strength of the La Nina, Christy said.
Calhoun County residents could be forgiven for wondering whether the federal government has the resources to re-spond to massive and widespread destruction and whether something remarkable isn’t going on with the weather.
The government’s answer to those pondering such questions is “yes.”
“The resources have been put in place will continue to be in place,” said William C. Lindsey, FEMA regional spokesman. “FEMA is a robust organization that has been working on disasters since our inception.”
Joplin is going to be “the next situation” for FEMA, Lindsey said. But the federal agency will keep “boots on the ground” and continue to make sure people get assistance in Calhoun County and throughout the state, he said.
More than 72,000 individuals and households had registered with FEMA and more than $45.3 million in federal aid had been approved as of May 20, according to the agency.
The federal relief agency has worked an average of 34 declared disasters per year since 1953, data from its website show. There had already been 36 declared disasters across the country by May 20, an above average total overall but off the record pace set last year. A total of 81 disasters were declared in 2010 – 46 by May 24, according to FEMA’s website.
As folks across Alabama hope for a quiet summer, meteorologists are turning their focus toward the upcoming hurricane season, which begins June 1.
Between 12 and 18 named storms are expected, with six to 10 hurricanes and the potential for three to six major hurricanes, according to the Climate Prediction Center of the National Oceanic and Atmospheric Administration. An average year consists of 11 named storms, six hurricanes and two major hurricanes.
The good news is that 1974 –- which had a similar winter and spring as 2011 and also came on the tail end of a La Nina year -– had a “limited activity in the tropics,” said Unger, a meteorologist.
La NiÒa conditions dissipated in mid-May, according to the International Research Institute for Climate and Society. A chance remains that conditions could resurface during the summer, but they most likely won’t, the institute says.
The last time the world came out of a La Nina cycle was in 2005 –- a “very active hurricane season” that saw Hurricane Katrina, Unger said before listing the above-average predictions for the 2011 hurricane season.
“It’s not absolute,” Unger said. “But that’s why we’re really going to start focusing on the tropics this year.”
Star staff writer Jason Bacaj: 256-235-3546