ASHLAND, N.H. — A 7-year-old Rhode Island girl was killed when two brooks merged into a raging torrent and swept her family’s SUV 100 yards downstream at a campground where they were staying.

Witnesses said the girl’s father stepped out of the car to check conditions just before the vehicle was swept away on Thursday, then jumped into the water to try to save his family.

His wife and 5-year-old son were rescued after clinging to a tree in the raging water for more than an hour Thursday evening.

“We heard the man screaming bloody murder,” camper Theresa Simione said yesterday. “He was screaming, ‘Help, help. The car is in the water. My family’s in the car. Call 9-1-1. Help me, Help me.’ ”

“It’s nothing I’m ever going to get out of my head,” said Simione, 41, of South Glens Falls, N.Y.

Fire Chief Tom Stewart said the man was on the other side of the river by the vehicle yelling for help.

Stewart believed the family was fleeing the flash flood at the Ames Brook Campground when the tragedy struck. He said the boy was in stable condition yesterday at Dartmouth Hitchcock Medical Center, in Lebanon.

The family asked officials not to release their names until they had notified other family members.

Chris Harris, head of the Swiftwater Rescue Team, helped rescue the mother and boy around 7 p.m. Thursday.

“The water had her pinned against an apple tree and she was holding onto her son,” Harris said. “She was yelling for help: ‘I can’t hold onto him much longer. You need to give me some help.’ ”

Harris said most of the woman’s clothes were torn off by the raging water. Her son was unconscious and both were hypothermic.

The girl’s body was found trapped in the crumpled SUV around 9 p.m., when the water receded.

Stewart said the flash flood followed a downpour, the latest in a series of rainstorms to hit the area in recent days.

“It poured so hard you couldn’t see two feet in front of you for a really long time,” Stewart said.

About 29 people were evacuated from the campground and put up in hotels, he said.

Stewart said a man who lives near the campground reportedly cut a path through the woods with a chain saw to help people get out.

Camper Herb Flick watched as events unfolded.

“There was so much roar from the water rushing, it’s amazing the Fire Department heard the screams,” said Flick, 69, of Milford, Del.

In the last two weeks, repeated thunderstorms have swelled rivers and streams and swept three people to their deaths. A tornado, rare in New Hampshire, killed a woman in her home on July 24.

Heavy rain and runoff from Thursday’s storms caused a sinkhole about 50 feet wide and 12 feet deep in the Weirs Beach section of Laconia. It also washed out part of the boardwalk at that tourist town on Lake Winnipesaukee and undermined a stretch of railroad track.

Lightning started a fire at a plant nursery in Laconia, where firefighters also had to rescue a family trapped in a car.

Crews cleaning up yesterday kept their eyes on the skies as more rain fell and still more was predicted.

“Our big concern now is that potentially, we are not out of this,” said Jim Van Dongen, state emergency management spokesman.