NEW YORK (AP) — Heavy rain spawned extreme flooding in New York’s Hudson Valley that killed at least one person, swamped roadways and forced road closures on Sunday night, as much of the rest of the Northeast United States (US) braced Monday for potentially punishing rains.

As the storm moved east, the National Weather Service extended flash flood warnings into Connecticut, including the cities of Stamford and Greenwich, before creeping into Massachusetts. Forecasters said some areas could get as much as five inches (12 centimetres) of rain.

In New York’s Hudson Valley, rescue teams found the body of a woman in her 30s who drowned after being swept away while trying to evacuate her home, Orange County Executive Steven Neuhaus told WABC-TV. Officials were waiting for the medical examiner’s office to arrive, he said.

“There’s a major flash flood. Major washouts were all around where her house is,” Neuhaus said. “So I could definitely see where she was trying to get out to safety, but did not make it, got swept away.”

The force of the flash flooding dislodged boulders, which rammed the woman’s house and damaged part of its wall, Neuhaus told The Associated Press. Two other people escaped.

“Her house was completely surrounded by water,” he said.

“She was trying to get through (the flooding) with her dog,” he added, “and she was overwhelmed by tidal-wave type waves.”

The extent of the destruction from the slow moving storm, which pounded the area with up to 8 inches (20 centimetres) of rain, won’t be known until after sunrise, when residents and officials can begin surveying the damage. But officials said the storm had already wrought tens of millions of dollars in damage.