LADY LAKE, Fla. -- Pulling blue tarps over the houses that still had walls, neighbors, jail inmates and National Guard troops picked up amid rain showers Saturday from dead-of-night thunderstorms that chewed through the middle of Florida, killing at least 20 people.

The victims ranged from a 92-year-old man to 17-year-old Brittany May, killed by a falling tree that crushed her bedroom.

President Bush designated four central Florida counties as disaster areas, releasing millions of dollars in aid for recovery and individual assistance.

"It makes you sick to your stomach for what we saw," David Paulison, director of the Federal Emergency Management Agency, said after touring the area Saturday morning with Gov. Charlie Crist.

At least one tornado, with winds estimated at up to 200 mph, hit between 3 and 4 a.m. Friday, when few people were awake to hear tornado warnings on radio and TV.

The cleanup task was daunting Saturday as showers soaked roofless homes, and piles of twisted aluminum siding, bricks, belongings, tree limbs and lumber. Power lines were down and traffic signals out in many areas.

Neighbors helped Sherry Reeves, 48, sort through her belongings and patch a big hole in her roof. Reeves was amazed that her home wasn't leveled like hundreds of others in this area about 50 miles north of Orlando.

"The Good Lord slipped and missed, or luck of the draw," she said.

The governor, handling the first natural disaster since he took office, said some stricken areas looked like "the surface of the moon." Crist canceled plans to attend Sunday's Super Bowl in Miami to stay in central Florida.

Crist praised the residents and charitable groups who pitched in to help clean up. Neighboring Marion County sent a group of low-risk inmates, dressed in green-and-white striped jail clothes. Some religious groups served food to rescue workers and victims, while about 40 National Guard members distributed blankets, food and water.

"This is not just government. This is people helping people and doing what's right," Crist said at a news conference with Paulison, U.S. Sens. Bill Nelson and Mel Martinez and other officials.

Paulison said his agency, criticized for inadequate response to Hurricane Katrina and other disasters, had housing trailers, water trucks and other aid already on the way. Bush's disaster declaration for Lake, Sumter, Seminole and Volusia counties also frees up loans and other assistance to individuals.

Tate Tapscott, 38, who lives in an area called Cooter Lake, went looking for neighbors after the storm and found a father and son dead, buried under debris.

"He was still holding on to his son," Tapscott said.

Lake County Sheriff Gary Borders said Saturday he did not expect to find any more fatalities. "We think that everyone is accounted for," Borders said.

Retired school bus driver Jamie Wright had fled South Florida a year ago to escape hurricanes, looking for a peaceful life farther north. Wright, 55, and her boyfriend Donald Lamond, 49, operators of a produce stand, were killed in their bed.

"We survived Hurricane Andrew in Homestead and it looked just like this," her son, Bryan McKiness, said as he collected mementos from the wreckage of his mother's home. "Mom said she'd had enough of hurricanes so she moved here. ... She was enjoying the good life."

The National Weather Service sent teams to study the damage for clues to the intensity and path of the thunderstorms that hit the area. Dave Sharp, a meteorologist with the weather service's office in Melbourne, said they suspected the region was struck by more than one tornado.

The main damage occurred along a 70-mile, west-to-east path with at least one break between Lady Lake and Paisley.

In the Paisley-Lake Mack area, a twister may have reached the fourth level of a new five-point tornado intensity scale, putting its wind speed at 166 mph to 200 mph, said Bart Hegemeyer, a member of the weather service research team. "It was incredibly strong," he said.

The wind picked up one tractor-trailer rig and slammed it down on top of another one. A church built to withstand a Category 4 hurricane was destroyed.

"To me it sounded like a mountain coming down," said Denise Anderson, 52.

Associated Press reporters Kelli Kennedy, Brian Skoloff and Ron Word in Lake County and Suzette Laboy, Adrian Sainz, Sarah Larimer, Laura Wides-Munoz and Curt Anderson in Miami contributed to this report.