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An avalanche of snow slid off a cabin roof in Idaho on Friday, burying three young girls, one of whom has died, officials said Saturday.

The "freak accident" happened around 5:30 p.m. local time in Macks Inn, a winter recreation community in Island Park, part of Idaho's Caribou-Targhee National Forest, said Fremont County Sheriff Len Humphries.

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A pair of 7 year olds and a 2-year-old, all sisters, were under the snow for a half hour, Humphries told NBC News.

The 2-year-old died of injuries after she was rushed to Eastern Idaho Regional Medical Center. The 7 year olds were in fair condition Saturday morning, Humphries said.

First-responders recovered a two-year-old under a pile of snow and large block of ice in Island Park, Idaho. EastIdahoNews.com

The girls had been staying with family at a private cabin. Temperatures and snowfall have been above average this winter, which may have triggered the deadly avalanche, according to Humphries. He added that he was not aware of any town ordinance that requires homeowners to clear snow off their roofs.

Humphries told EastIdahoNews.com that "this was a freak accident."

"It was heart-wrenching for the dispatchers and EMTs and firemen and everyone who responded. Our prayers are with the kids and their families," he said.

Names of the children were not released.