Concord, N.H. ? Torrential rain forced hundreds of people from their homes in parts of New England on Sunday, as water flowed over dams and washed out roads.

The governors of New Hampshire and Massachusetts declared states of emergency, activating the National Guard to help communities respond to the storm. Maine’s governor also declared a state of emergency for one county.

“It’s a very serious situation,” said New Hampshire Gov. John Lynch, adding that forecasters were predicting 12 to 15 inches of rain by the end of the storm in parts of southern New Hampshire. “It continues to change and the situation continues to worsen.”

In some towns, police and fire crews used boats to get people out of their homes and stranded cars after hundreds of roads were damaged. Others got around in kayaks. Some towns shut down, not letting anyone pass except emergency vehicles.

“The town is cut right in half,” said Glenn Laramie, police chief in Andover, N.H.

A dam in Milton, N.H., was in danger of failing, which could send a 10-foot wall of water downstream, the National Weather Service said in a bulletin. People downstream were being evacuated in the town.

A York Beach, Maine, resident escorts a canoe filled with belongings through a flooded street outside his house. Torrential rain washed out roads and forced some people from their homes early Sunday.

The state Office of Emergency Management said at least a dozen dams were being closely watched.

In Massachusetts, cars were pulled from flooded streets in downtown Peabody, about 20 miles north of Boston, and about 300 people were evacuated from an apartment complex for seniors. Businesses stacked sandbags at their doors, trying to prevent damage from water that at one point rose to waist-deep.

“I have no heat, I have no hot water, and my cellar is flooded up to its tippy top,” said Esther Gibely, who sought shelter at Peabody Veterans Memorial High School.

About 150 residents in Melrose, Mass., had to leave their homes after sewage lines were overwhelmed, backing up into houses, said Massachusetts Gov. Mitt Romney.

About 10 communities in the northeast section of the state opened temporary shelters, Romney said.

Some parts of New Hampshire had seen 7 inches of rain by midday Sunday and forecasters said up to 5 more inches might come during the day.