An estimated 80 tornadoes pummeled Missouri, Kansas, Tennessee and Arkansas states late Sunday, destroying homes, buildings and anything else in their paths.

Thirteen people were killed in Tennessee, 12 people in Missouri and seven in Kansas.

President George W. Bush, speaking in Little Rock, Arkansas, promised speedy assistance where needed. "Nature is awfully tough at times," he said in a speech.

The town of Pierce in southwestern Missouri -- one of the areas that bore the brunt of what meteorologists called a "perfect storm" -- was essentially flattened.

Wreckage from shattered homes and snapped trees was strewn across a wide area. Red Cross officials set up a shelter to take in the 300 people out of a population of 1,382 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."

The town's turn-of-the-century buildings were not built to withstand tornadoes, said Crystal Payton, spokeswoman for the Federal Emergency Management Agency (FEMA) in the Midwestern region.

Missouri Governor Bob Holden called up the National Guard to help with the clean-up, and dispatched canine search and rescue teams and hazardous material teams to the 17 worst hit counties.

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

"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.

There were at least five tornadoes across Kansas state Sunday, according to Emergency Management Agency officials.

In one Kansas city suburb, Dale Wilch watched from his driveway as a tornado dropped out of the clouds and touch down across the street.

"I saw it coming, jumped up and went down to the basement," Wilch said.

"As soon as I saw the tornado 100 feet (30 metres) from my house, I knew there was nothing we could do to save what we had."

As Wilch headed inside, the tornado turned sharply north, cutting through another neighborhood. Wilch's house escaped with minor damage.

William Jewell College in the historic town of Liberty, Missouri, 11 miles northeast of Kansas City, was forced to close for the rest of the academic year because of the damage.

Winds knocked down a new clock tower and caused serious roof damage.

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

In Tennessee, the fatalities were concentrated in the western part of the state.

"We've got 13 confirmed dead, 11 of those in one county," said Kurt Pickering with the Tennessee Emergency Management Agency.

In Jackson, Tennessee, utility companies struggled to restore power and running water.

"We've got 27,000 people without power (and) most of the city without water," said Jackson's mayor Charles Farmer.

Meteorologists warned that bad weather predicted for Monday and Tuesday would hamper recovery efforts.

The mayhem began when cold dry air from the Rocky Mountains in the western United States and moist warm air from the Gulf of Mexico collided in the central United States.

"It was a pretty perfect setup for severe weather," said Kelli Tarp of the National Oceanic and Atmospheric Administration's storm prediction center in Norman, Oklahoma.

SPACE.WIRE