Blame La Nina. The surface cooling of the eastern and central Pacific Ocean has shifted traditional weather patterns that produce deadly tornadoes farther east into Tennessee.

“If I were in the South or Ohio Valley, I’d be extra prepared this year,” cautions Mike Smith, senior vice-president of AccuWeather Enterprise Solutions, a leading worldwide weather forecasting company. “There is no way to know if it (2012) will be as active as last year.

“We know that La Nina, the cooler than average water in the equatorial Pacific off South America, tends to move the more vigorous tornadoes farther east, which has been the case since 2010,” Smith explains. “The La Nina is now breaking up, so I would anticipate (Tennessee will be more of a) tornado alley in the next two years.”

The 2011 tornado season was the deadliest in 75 years in the U.S. and the fourth deadliest ever recorded.

Between Jan. 1 and March 4 of this year, there were 274 tornadoes nationwide, preliminary data from the National Weather Service’s Storm Prediction Center reveals. There is an average of 1,300 tornadoes a year in the US, but in 2011 there were 1,709.

“Last year we had two unfortunate occurrences simultaneously, a larger-than-normal number of tornadoes plus tornadoes hitting densely populated areas,” Smith adds. “There is no way to know if the cities are going to be hit in the same number as last year. If so, it could be another deadly year.”

Damages made by tornadoes and extreme storms often overshadow those connected to other high-profile catastrophes such as hurricanes and floods. Insurance Information Institute figures show hurricanes accounted for $5.5 billion in claims in 2011, while the price tag for tornadoes/severe thunderstorms was $25.8 billion. Flood damages were an estimated $535 million.