Rescue crews in helicopters and four-wheel-drive vehicles searched through the steep valleys of Appalachian coal country today after flash flooding left at least four people dead and 12 missing.

Five inches of rain fell in six hours on Thursday, sending streams and rivers surging out of their banks in the mountainous area where West Virginia, Kentucky and Virginia meet.

Some communities were cut off by mudslides, while others had water up to the eaves of homes in a deluge so powerful that people lashed themselves to trees. More than 100,000 homes and businesses lost power at the peak of the storm.

"It was like the mountain just opened up and water started to come out," said Brenda Blankenship, postmaster of tiny Hurley, Va. "Everything is demolished. All the businesses in Hurley are gone, houses are gone. They're just gutted."

At least three people in West Virginia and one in Virginia were killed. Authorities spent today looking for at least 12 people reported missing: eight in West Virginia, three in Virginia and one in Kentucky.

"People were tying themselves to trees. They couldn't get helicopter assistance in. It was awful," said Vicky Jones, a dispatcher with the Buchanan County, Va., Sheriff's Office.

The Tug Fork River, which separates West Virginia from Kentucky for miles, rose steadily today. Officials in Williamson, W.Va., closed the flood doors for the first time in their 18-year existence, but parts of the community of 3,400 people were already swamped.

Across the river in Kentucky, about 350 homes were evacuated. Dozens of people gathered on the roadsides overlooking Goody, Ky., and watched as the murky waters covered their yards. In some places, only rooftops could be seen.

Others were more fortunate.

"In the last flood, I had to be taken out by boat. At least this time I had enough warning," said Vickie Taylor-True, who spent the morning carrying valuables from her home in Hardy, Ky.

The office of Virginia Gov. Mark R. Warner (D) said about 200 houses in Buchanan County were damaged or destroyed. An undetermined number of structures were damaged in Kentucky. In West Virginia, Gov. Robert E. Wise Jr. (R), who toured the area by helicopter and on foot today, estimated that at least 375 homes and 30 businesses were damaged.

McDowell County, W.Va., was hard hit again, just 10 months after devastating floods damaged hundreds of homes there.

"It's worse here than it was last time," said State Police Capt. R.L. Hall, who was in the nearby town of Mullens when it was devastated last year. "From one end of the county to another, it's all under water."

All of West Virginia's dead and missing were in McDowell County, where more than a dozen highways were impassable and searchers had to rely on helicopters.

"It could be a situation that the people are not accounted for because they went to a shelter or a friend's home to get away from the high water," said Mark Rigsby, a West Virginia emergency services spokesman.

Several water systems in the county were shut down after the runoff sent waste from an old coal mine into the water supply. Mudslides also left the town of Bradshaw virtually inaccessible.

Floodwaters smash a bridge along U.S. 52 near Williamson, W.Va. The flash flooding was so severe that some residents lashed themselves to trees.