Perilous Times and Climate Change
El Nino will whip up a more active and vicious tornado season
By William M. Welch, USA TODAY
Weather forecasters say the wetter-than-usual El Niño winter that has
blasted much of the United States could be followed by an active
tornado season.
Greg Forbes, severe weather expert at the Weather Channel, said Tuesday
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 in the USA they are most common
in the first half of the calendar year.
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.
Only one tornado, in California, was reported in February. On Monday, a
strong twister ripped through western Oklahoma. No injuries were
reported.
Greg Carbin of the Storm Prediction Center in Norman, Okla., told the
Associated Press there will be an uptick in thunderstorm activity as
the Southern Plains states warm up.
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 fewer than average tornadoes in 2009, Forbes
said.
Although data is 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.