LEBANON, N.H. — The brook behind Pam Green’s home had turned into “a tidal wave,” the water was knee-deep in her backyard and the rainfall created “a beautiful little waterfall we never had before,” she said, describing some of the effects of flash flooding that hit New Hampshire.

The city of Lebanon had received nearly 2 inches of rain in 45 minutes on Tuesday. “I’ve lived here my entire life and I’ve never seen this amount of water,” said Green, 54. She pointed out cantaloupe-sized rocks pushed by the water into her front yard.

Gov. Maggie Hassan declared a state of emergency on Wednesday after flash flooding washed out a number of roads in New Hampshire and covered others with mud. There have been no reports of injuries.

Hassan said the state received nearly 4 inches of rain in 24 hours and the ground was saturated. State and municipal roads alike were affected, especially in the western part of New Hampshire.

About 100 yards from Green’s home, flash flooding created a gash that was 40 feet long, 2 feet wide and 25 feet deep on state Route 120, the main connector between Lebanon and Claremont. A water main had burst, leaving about 100 homes in the area without water.

Residents of Slayton Hill Road lost power after a wave of water rolled down the steep street. At the bottom of the road was a big mound of dirt higher than a house.

“I guess this is what you’d call our ‘Little Irene,’ ” said Tim White, who lives on the street, recalling the August 2011 tropical storm that caused flooding in parts of Lebanon.

White lives at the top of the hill. The street is closed indefinitely. “I’m probably one of the more fortunate ones,” he said. “Everyone down from us is land-locked.”

Authorities said Sullivan, Cheshire and Grafton counties received the most damage.

In Lebanon, 66 local roads were affected, said Jim Van Dongen, spokesman for the Division of Homeland Security and Emergency Management.

State officials say 100 to 150 homes in the town of Washington were cut off from any access to emergency services after a road and temporary bridge were washed out. The road was expected to reopen later Wednesday.

Some people were evacuated in Westmoreland early Wednesday.

The National Weather Service extended a flash flood watch through Wednesday night in Cheshire and Hillsborough counties.