An estimated 60 tornadoes pummeled sections of Missouri, Kansas, Tennessee and Arkansas for hours Sunday, laying waste to homes, buildings and industrial parks and wiping some small towns virtually off the map.

In southwestern Missouri, the town of Pierce (population 100,000) -- one of the areas that bore the brunt of what meteorologists are calling a "perfect storm" -- was essentially flattened.

Aerial footage showed pulverized homes and wreckage strewn in every direction, and Red Cross officials had set up a shelter to take in the 300 people who had been left homeless by the devastation.

"A lot of people are turning to their relatives and friends across the state," said Red Cross spokesman Michael Spencer.

"The Red Cross is going to be in this community for many, many weeks, helping these people to get back on their feet, because they have no one else to turn to right now."

"This is the worst damage I've seen from a tornado in several years," Missouri Governor Bob Holden said following a visit to a devastated neighborhood in Kansas City.

The storm claimed at least 12 casualties in Missouri, where softball-sized hail fell in some areas as high winds toppled power lines and funnel clouds ripped off roofs and flattened neighborhoods.

"We've got hundreds of walking wounded" and "enormous amounts of damage," said Steve Sloan with the State Emergency Management Agency in Jefferson City, Missouri.

Police armed with shotguns patrolled Kansas City's historic Liberty Square after the storm ripped roofs off four businesses. Bricks littered the streets.

Across the state of Kansas, at least five tornadoes touched down Sunday, killing seven people, according to officials with the Emergency Management Agency.

One twister was 457 meters (500 yards) wide when it hit Leavenworth County, Kansas, at around 3:30 pm (2030 GMT) Sunday, according to National Weather Service meteorologist Lyn Maximuk.

Kansas Governor Kathleen Sebelius declared seven counties disaster areas, and officials stopped all flights and evacuated terminals at the Kansas City International Airport.

In the state of Tennessee, 10 people died, mostly in the western third of the state, and that number was expected to rise.

"We expect that number to get into the teens. We're pretty sure there are more casualties that haven't been recovered yet," said Kurt Pickering with the Tennessee Emergency Management Agency.

Recovery efforts were likely to be hampered by continuing bad weather, meteorologists warned.

"We're predicting severe weather for the rest of Monday and Tuesday," said Kelli Tarp, with the National Oceanic and Atmospheric Administration's storm prediction center in Norman, Oklahoma.

"This is a very slow-moving system."

SPACE.WIRE