Tornado alley is deserted
AdvertisementFor the first time in more than 60 years, the United States has had a month without a single tornado.
During February the US would expect to see an average of 22 tornadoes hitting the ground. Despite 2010 being an El Nino year, which raises the risk of tornadoes forming, none were seen.
Tornadoes form in the US when cold air over the northwest collides with warm tropical air coming in from the southeast and Gulf of Mexico.
Normally the two air masses run into each other over the Great Plains of the Midwest, which provides the perfect environment for the monster storms to amass, but this year the jet stream has buckled unusually south over Texas and the southern states, bringing with it the cold air.
With the jet stream blocking the warm air pushing north, the residents of the Great Plains have had a quiet month.
Tornadoes are one of weather's most violent occurrence and can see wind speeds in excess of 300mph. Rotating columns of air which form in thunderstorms, it is only when these funnels hit the ground that they are called tornadoes.
The Fujita scale, which measures tornadoes, does not gauge the storm on wind speed but on damage done.
This could mean a less violent storm hitting a residential area being graded the highest F5 tornado, while a monster storm over an unpopulated area could be graded the lowest, F1.
