Pictures of Tornadoes – and their Devastation

A rare 'mother ship' cloud formation hovers over Childress, Texas. Tornado chasers there spent seven hours and 150 miles tracking the supercell thunderstorm that produced this cloud formation. Supercell thunderstorms are known to spawn tornadoes with winds exceeding 200 miles an hour.

Tornado chasers hustle as a storm approaches in South Dakota. The state is part of 'Tornado Alley,' an area of the Midwest United States that tends to see more severe tornadoes than the rest of the country.

Storm-stained skies hover over the remains of a mobile home demolished by a passing tornado. Tornadoes kill about 60 people in the U.S. every year and cause billions of dollars of property damage.

A photographer caught this extreme close-up of a tornado funnel in Manchester, South Dakota. The combination of high winds, flying debris, and loud noise of the tornado would have made this photographer very uncomfortable.

Heavy clouds hang low over a dilapidated homestead in the Midwest, foretelling a possible tornado. Tornadoes form when the updrafts that supply storms with warm, humid air become a vortex, or high-speed whirlwind.

An EF5 tornado threw a van into a hotel in Greensburg, Kansas. An EF5 tornado produces winds greater than 200 miles per hour (322 kilometers per hour), and can pick up and throw vehicles and destroy buildings with ease.

A waterspout touches down close to a boat near Dubrovnik, Croatia in August 2007. Waterspouts are weak tornadoes that happen over warm water. They can move onto land and become tornadoes.

A thin funnel cloud touches down in a field in northwest Iowa. Funnel clouds become tornadoes once they touch the ground.

A man and woman clean up the debris from their apartment that was damaged by a February 2008 tornado over Lafayette, Tennessee.

Several homes in a row were destroyed by a May 2008 tornado in Parkersburg, Iowa. Tornadoes can completely destroy some buildings while leaving others intact, depending on their construction. Mobile homes are notoriously flimsy in tornadoes.

A category F3 tornado swirls across a South Dakota prairie. The F (Fujita) scale was used to measure wind speeds based on damage left behind after a tornado, and an F3 tornado had wind speeds between 158 and 206 miles an hour. The United States now uses theEF (Enhanced Fujita) scale, which takes more variables into account when assigning wind speeds to a tornado. An EF3 tornado now has wind speeds between 136-165 miles per hour, and the tornado pictured could be an EF3, EF4, or EF5.

A woman searches the wreckage of her mother's house in Arkansas after a tornado removed the roof. Forecasters in the United States can give an average warning time of 13 minutes before a tornado hits. The best place to be in a tornado is in a basement or interior room of the lowest floor of a sturdy building.

A Kansas vehicle license plate impaled on a tree after an EF5 tornado struck Greensburg, Kansas. Flying debris is the main cause of injuries and deaths in tornadoes.

A woman looks through a broken window of a friend's house after a tornado over Atkins, Arkansas. Despite a myth that says otherwise, opening windows to equalise the pressure between the inside and outside of a house during a tornado will not prevent them from breaking. Flying debris is the main cause of broken windows in tornadoes.

A broken safety glass window frames a destroyed house after an EF5 tornado struck Greensburg, Kansas.