Weather forecasters say the wetter-than-usual El Niño winter that has blasted much of the nation could be followed by an active tornado season.

Greg Forbes, severe weather expert at The Weather Channel, said Wednesday that comparable past winters suggest there could be an above-average number of tornadoes this year. "The average was 9% more tornadoes than a typical year," he said.

El Niño is a seasonal weather pattern in which warm equatorial winds that periodically push toward the West Coast send moist air to the nation's interior.

Tornadoes can happen at any time, but they are most common in the first half of the year in the US.

The 2010 tornado season has had a slow start, with 44 tornadoes reported through Monday, according to the National Weather Service. The average number for this time is 162, according to the weather service.

Two tornadoes, in California, were reported in February. On Monday, a strong twister ripped through western Oklahoma. No injuries were reported.

Forbes said the likelihood of more tornadoes was offset a bit by weather patterns that have made the Gulf of Mexico's temperatures 2 or more degrees lower than usual, causing airflows to be a little cooler and less moist. He said a lack of moisture reduces the likelihood of tornadoes.

The nation experienced a fewer-than-average number of tornadoes in 2009, Forbes said.

Although data are not yet final, The Weather Channel counted 1,145 tornadoes last year, compared with 1,272 in an average year. The federal Storm Prediction Center counted 1,156 tornadoes last year, which killed 21 people. (Source: USA Today)

Story Date: September 2, 2010