Monster tornadoes cause widespread devastation

Severe U.S. storms lead to the greatest number of February tornadoes since 2008, causing devastation as far north as Vermont.

On February 22 and 23 a severe weather outbreak in the South and Mid-Atlantic U.S. resulted in 31 tornadoes. The twisters damaged over 340 buildings and mobile homes, causing 111,000 power outages and killing at least seven people across more than a dozen states.

What was unusual about this particular event was how far north the severe weather stretched, according to RMS manager Jeff Waters. “Severe thunderstorm watches were in effect as far north as Vermont and parts of Massachusetts,” he said. “The last time western Massachusetts experienced a severe thunderstorm warning was in February 1997.”

“Some may also be wondering about the connection between the strong El Niño phase currently taking place in the Pacific, and the severe weather,” he continued. “The El Niño Southern Oscillation (ENSO) phase may have some influence on the frequency of tornadoes, but it’s difficult to differentiate the large factors from the many small-scale factors. El Niño does not, by itself, spark tornados or severe weather outbreaks.”

While historically it is Atlantic hurricanes that have caused the largest U.S. catastrophe claims, severe weather and tornadoes have been responsible for the most costly events in recent years. Last year’s El Niño was credited for another benign hurricane season in the North Atlantic, however a February winter storm in the U.S. was the largest lossmaking natural disaster of the year, resulting in insured losses of over $2bn, according to Swiss Re Sigma.

Insured losses due to natural disasters in the U.S. in 2015 totaled $16bn, according to Munich Re. Severe thunderstorm losses, at $9.6bn, accounted for about 60% of the total with two tornado outbreaks in December in the southern states contributing to some of the highest losses.

Annually, about 1,000 tornadoes are reported nationwide in the U.S., according to the National Oceanic and Atmospheric Administration. Tornado intensity is measured by the enhanced Fujita (EF) scale of 0 through 5. During February’s outbreak at least six tornadoes were rated EF2 or stronger, with at least EF3 damage from a tornado that hit near Pensacola, Florida


April 2016