GOWANDA - An 80-year-old man died after being swept away by floodwaters and another man died of an apparent heart attack after flooding prevented emergency crews from reaching him as thunderstorms knocked out power to thousands across western New York, authorities said Monday.

Gowanda, a rural valley town of 2,600 people 30 miles south of Buffalo, appeared to be one of the worst-hit areas. A hospital was evacuated and more than 80 residents spent the night in a school after swollen creeks breached their banks Sunday, flooding homes and streets overnight. Of the town's 1,000 or so homes, 300 to 400 were damaged, authorities said. The National Weather Service said gauges in Cattaraugus Creek in the Gowanda area showed the water rose 5 feet in five minutes, from 6.36 feet at 11:30 p.m. Sunday to 11.45 feet at the next reading.

“The water was just rolling down the road,” said Jacqueline Traffanstedt, 71, who was rescued early Monday by stepping into the bucket of a front-end loader that drove up to her water-ringed house. Cars parked along the road, she said, were turned “sideways from the force of the water.”

Gov. David Paterson declared a state disaster emergency and promised help for Cattaraugus, Chautauqua and Erie counties.

Theodore E. Stitzel, 80, of Gowanda had gone out to check on a bridge on his property late Sunday after a creek near his home overflowed, Cattaraugus County police said, and he lost his footing and drowned. Authorities estimated the water was 8 to 9 feet above flood stage. His body was recovered early Monday.

Authorities also received a 911 call about 2 a.m. from an elderly man whose street was under water. EMTs had to use a front-end loader to reach the man's house, but he apparently died of a heart attack, Gowanda disaster coordinator Nick Crassi said. Crassi didn't know whether the man would have survived had emergency workers been able to reach him more quickly. Authorities would not release the man's identity Monday afternoon.

In nearby Zoar Valley, seven people were rescued by helicopter from a flooded campsite Monday morning.

“They were hanging on to cars and trailers,” Erie County Sheriff's spokeswoman Mary Murray said.

County emergency officials issued a ban on unnecessary travel in the Gowanda and surrounding areas, where some streets were still under water Monday and others were coated with mud and littered with tree branches.

Authorities said the storms toppled trees and power lines, and severe flooding was also reported in nearby Silver Creek, where dozens of trailers in a mobile home park were lifted from their lots.