Floodwaters started to back down Monday after a weekend deluge left thousands of people scrambling for higher ground.

Twenty rivers overflowed their banks, and highwater marks for five of them set records. Rainfall set rec-ords too, with 5.82 inches in Olympia and 3.56 inches at Seattle-Tacoma International Airport during the 24 hours ending Saturday afternoon.In Seattle, officials said the weather contributed to the collapse Sunday of a closed floating bridge across Lake Washington.

One section that sank severed cables anchoring a newer bridge, closing Interstate 90 indefinitely and creating a nightmare for commuters between the city and suburbs east of the lake.

Sixteen highways and dozens of local roads remained closed early Monday. Gov. Booth Gardner issued an emergency declaration for 12 counties, bringing to 17 the number for which federal aid has been sought.

The state is still reeling from flooding in five counties two weeks ago that caused an estimated $40 million in damage.

"My state is falling apart on me," Gardner said Sunday.

More rain was forecast for Monday, but colder weather was expected to ease the flooding by holding precipitation as snow in the upper watersheds, National Weather Service specialist Patrick Brandow said.

At least 3,000 people across the state fled their homes over the weekend because of the flooding. Thirteen Red Cross shelters remained open Sunday night.

Gen. Gregory Barlow, head of Washington National Guard, said an area about 40 miles northeast of Seattle appeared to be hardest hit, with water covering the roofs of houses.

One man was missing and presumed drowned after he drove past a barricade and into the floodwaters of the Snoqualmie River early Sunday, police said. His wife and infant daughter were rescued.

State transportation engineers and police closed the new seven-lane I-90 bridge between Seattle and Mercer Island, which carries an average of about 110,000 vehicles a day, after the old floating bridge which parallels it collapsed. They feared loose pieces of the old bridge could damage it.