Tornadoes Peak Earlier in Tornado Alley

Tornado activity in the heart of "Tornado Alley" in the central and southern Great Plains is peaking earlier than half a century ago - up to two weeks earlier, according to a new study.

The states of Nebraska, Kansas, Oklahoma, and northern Texas historically are areas of high tornado activity, giving them their name "Tornado Alley."

According to the study, published in the journal Geophysical Research Letters, the shift can't be pinned on a single cause, but scientists suspect that climate change may play a big part.

For some states and for stronger tornadoes, the season - which runs from early May to early July - now starts an average of 14 days earlier compared to the 1950s.

"If we take Nebraska out [of the data], it is a nearly two-week shift earlier," John Long, a research scientist at Montana State and the paper's lead author, said in a statement.

This two-week shift also applies to tornadoes rated above F0, the lowest rung on the original Fujita scale of tornado strength.

F1 tornadoes have winds between 73 and 112 mph, while the strongest tornadoes, F5, boast wind speeds between 261 and 318 mph, according to the original Fujita scale (the scale was updated in 2007, but most of the study' data originates in years prior).

The findings, if true, could help states in "Tornado Alley" better prepare for these violent storms.

About 1,300 tornadoes hit the United States annually, killing an average of 60 people, according to the National Weather Service's Storm Prediction Center.

"From a public safety perspective, if this trend (of an earlier tornado season) is indeed occurring, then people need to begin preparing for severe weather earlier in the year," said Greg Carbin, the warning coordination meteorologist at the Storm Prediction Center in Norman, Okla., who was not involved in the new study.

While the researchers couldn't pinpoint any one reason for the shift in the tornado season, they say the findings are in line with what scientists has expected from a warming world.