Rain from the remnants of Tropical Storm Gaston inundated parts of Richmond and central Virginia last night, closing streets and prompting evacuation of low-lying sections of the region as floating cars bobbed against upper levels of buildings.

Authorities reported sightings of several tornadoes or funnel clouds as the storm swept northeastward from North Carolina, drenching parts of Virginia from Lynchburg to Richmond with as much as a foot of rain.

As winds gusted and trees toppled, electricity was knocked out to more than 100,000 homes and businesses, mostly in the Richmond area. Officials said openings of state offices in Richmond could be delayed by as much as two hours today.

Virginia Gov. Mark R. Warner (D) declared a state of emergency about 8:30 p.m. for hard-hit sections of the state, and said the storm made this year the state's wettest on record.

"We've gone from the driest year [two years ago] to the wettest," Warner said.

Officials feared last night that rapidly rising water might burst the dam at Falling Creek Reservoir in Chesterfield County in Richmond's suburbs, said Dawn Eischen, a spokeswoman for the state Department of Emergency Management. She said evacuation had been ordered below the dam.

"It's been sideways rain" in Richmond, said Kevin Hall, an aide to the governor. Intersections were "clogged with stranded and abandoned vehicles," he said, and many streets were still gridlocked at 11 p.m.

With sirens from emergency vehicles wailing in the background and city streets blocked by high water, Hall said that the governor's declaration made possible the rapid deployment of state agencies and employees for rescue and similar functions.

Warner, who was in Northern Virginia last night for previously scheduled events, said he was canceling an appearance on a Washington radio station this morning to return as soon as possible to the state capital.

He said he anticipated that two state office buildings, the Jefferson and the Madison buildings, would be closed today because of short circuits from flooded basements.

The storm was blamed for knocking out electricity to more than 105,000 homes and businesses in Virginia, according to Dominion Virginia Power. More than 89,000 of those affected were in the central part of the state.

Possible tornadoes were reported through the day in such spots as Poquoson, Hopewell and Appomattox Manor, where 25 to 30 trees were blown down. Sightings also were reported in Dinwiddie County, south of Richmond, where sheds were lifted and tossed around, and in York and New Kent counties, the National Weather Service said.

In addition to Richmond, flooding was reported in Henrico, Hanover and Lunenburg counties.

Relatively little rain fell in the immediate Washington area, as the storm headed across Maryland's Eastern Shore toward Delaware and New Jersey. Forecasts predicted clouds in the area today, then several clear days.

In Richmond, authorities said that waters rose rapidly in the low-lying historic downtown districts near the James River.

"It's flooded," said An Bui, owner of the Mekong restaurant in the city's Fan District.

With his business closed, he said he was stuck there, surrounded by "30 or 40 buckets" collecting water from the restaurant's leaking roof.

"You can't even see outside," he said. "That's how heavy the rain is."

Trees were falling and "cars are floating away," he said.

So it was around much of the city late last night. In the darkness downtown, with electricity still out, many streets east and west of the city remained impassible. Many autos were abandoned along Broad Street and Monument Avenue, two principal thoroughfares.

Matthew Marsili, an interior designer, told the Associated Press that he left work in the Fan District at 5:30 p.m. and hadn't reached his home across town four hours later.

While driving downtown, he said, "all of this water came rushing down the hill all at once. It half-submerged a bus in the middle of the intersection that was filled with people, and cars started floating down the road.

"There was this white Jeep Cherokee that went floating down the road and crashed into the bar at the bottom of Main Street," he said.

Staff writer Michael D. Shear contributed to this report from Richmond.

Kenny Shelton walks among vehicles parked in a flooded parking lot in Richmond.