INDEPENDENCE (AP) -- Powerful thunderstorms rolled across Iowa late Monday, adding to the rivers and streams that were already overflowing from the rain that fell last week and especially over the weekend.

"The rivers can't take any more," said Brad Fillbach, a National Weather Service technician.

Before the heavy downpours that struck late Monday, the statewide rainfall average over the past week was nearly 3.87 inches - the highest since July 1993.

In Independence, which was struggling with flooding from the weekend, it's hard for Amy Hare to know what is destroyed and what can be salvaged with so much of her family's belongings covered in dark, greasy mud.

The three-bedroom ranch home Hare rents is one of several in the neighborhood ravaged by an overflowing Malone Creek, a volatile stream that drains farm fields north of this eastern Iowa town of 6,000 people.

Hare said water forced its way into the basement through sealed windows Sunday morning, filling nearly to the rafters and leaving dolls, clothes, appliances and photographs with a coated thick film of pungent, sludge-like mud.

"It's just going to be a matter of going through things to know what's gone for good and what we can save," Hare said Monday as she swept leftover water and mud into the sump pump. "I know we lost some photographs, Polaroids, of my youngest daughter taken just after she was born. We're going to salvage what we can."

Two blocks away, floodwaters caved in the foundations of two homes less than 50 yards from the creek's banks. The owners, evacuated Sunday, were not among the dozens of other homeowners cleaning basements and surveying damage to vehicles, property and personal belongings Monday.

State Climatologist Harry Hillaker said Monday that although the weekend rainfall equaled that of the flooding in 1993, the threat isn't as ominous.

He said in 1993, Iowa was soaked with week after weeks of pounding rainstorms.

"We were fortunate this time that conditions were basically pretty normal until Friday," Hillaker said.

Storms moving across the state Friday, Saturday and Sunday produced a string of 19 tornadoes, hail, high winds and heavy rains - as much as 9 inches fell over the weekend near Ames. That was before the tornado-bearing drenchers moved in late Monday.

The National Weather Service reported that some of the heaviest rainfalls Monday night fell in central Iowa, where the Raccoon River was overflowing its banks. Van Meter reported 3.18 inches, Dallas Center-Grimes, 2.45, and parts of Des Moines 2.38.

The weather service reported there were some tornadoes that touched down. Reports of downed trees and power lines were reported in Appanoose County, where touchdowns were reported, but the weather service said it was unknown if the damage came from the tornadoes.

As many as 4,000 customers scattered throughout central Iowa were without power Monday night, MidAmerican spokesman Allan Urlis said. All were expected to have power back by Tuesday morning.

Gov. Tom Vilsack by late Monday had asked for a federal disaster declaration covering 24 counties: Black Hawk, Boone, Bremer, Buchanan, Butler, Cass, Cerro Gordo, Chickasaw, Clayton, Delaware, Fayette, Floyd, Fremont, Hancock, Howard, Humboldt, Johnson, Jones, Kossuth, Mitchell, Page, Pocahontas, Winnebago, and Wright counties.

Vilsack also granted state disaster declarations for the same counties, authorizing the state to provide sandbags, pumps, barricades and personnel for traffic control.

Iowa Emergency Management Director Ellen Gordon said she expects to hear about the federal disaster request Tuesday.

The greatest concern in central Iowa was the Raccoon River, which had been projected to crest at 20 feet - well over flood stage - in Des Moines late Monday night. Then came Monday's downpour. Now the river will crest "significantly higher," Des Moines Public Works Director Bill Stowe said.

The bridge on the pedestrian path at Gray's Lake was under water Monday night, and the river was still rising. Water poured across Fleur Drive, the main route to the Des Moines International Airport, which remained closed.

At the nearby Des Moines Water Works, officials closed floodgates that hadn't been used in six years. The gates are part of a levee system that was built to avoid a repeat of the record floods of 1993, when high waters from the Raccoon River swamped the plant, shutting off the city's water service.

Water Works General Manager L.D. McMullen said Monday that the top of the levees are 30 feet high, about 10 feet higher than river levels were at Monday night.

Elsewhere in Independence, evidence of the weekend's flooding remains.

Sandbags were piled around this town's historic business district and residents were pumping water out of basements in downtown buildings near the Wapsipinicon River, which last flooded in 1999.

Several homes along the river and the local Kent Feeds distributor were surrounded by about 4 feet of water. Floodwaters were pooling behind downtown buildings.

Townspeople were cheered by news that the river was receding, but were braced for Monday night storms.

"There is supposed to be more on the way and that's not so good. The ground all around the county is saturated and just can't take any more water," said Ed Fitzgerald, spokesman for Buchanan County Emergency Management.

Vilsack was set to visit Independence and Mason City on Tuesday to survey damage.

In Mason City, Cerro Gordo County Engineer Jim Witt said Monday that damage to county roads could reach $1 million.

"I wouldn't be surprised. There are 19 roads closed and 90 percent of county roads have water over them," he said.

"We're looking at months of cleanup and years of ditch cleaning, which is an on-going process anyway but is much worse now," Witt said.

The National Weather Service issued a flood warning for Waterloo, as the Cedar River was expected to crest around 19.6 feet Tuesday. City officials were already reporting flooding in low-lying areas of the city and surrounding farmland Monday morning.

In Manchester, workers were busy Monday cleaning up the mess left behind by the Maquoketa River.

The river spilled over its banks early Sunday but had receded by Monday, leaving dirt damage and two-foot tall sandbars in a path through the downtown business section.

Paul Roussell, general manager at a local car dealership, said his staff has worked around the clock to clean up their flooded garage in hopes of reopening for business Tuesday afternoon.

"This is the highest it's ever been for as long as I've known and have been told," said Roussell, who has worked at the shop for 15 years.