A skier has been rescued after being caught in an avalanche that was recorded on a mobile phone.
The avalanche dragged the woman into a Utah ravine and buried her in snow, but she survived because she deployed a special air bag and other skiers were able to quickly dig her out, witnesses said.
Joe Campanelli was using his phone to record the sun-drenched Wasatch mountains when the skier descended into a steep gully filled with loose snow in Grizzly Gulch, a short distance from the Alta ski area east of Salt Lake City.
"That is not a good slope to ski," Mr Campanelli can be heard saying on the video. Moments later, the slope breaks, and he says: "You're in a slide, bud."
The woman pulled a ripcord on an air bag-equipped backpack - a European-style safety device that is becoming more common in the Rocky Mountain back country.
Mr Campanelli abruptly stopped recording to help rescue the skier. His friend, Aaron Rice, said he used an avalanche beacon and a probe to find her location, then dug her out of several feet of snow, with help from others.
"She was breathing, talking," Mr Rice said. "She said, 'Thank you. I can't believe you got here so quickly'. She was completely shaken up."
The woman was swept about 100ft down the gully at an angle approaching 40 degrees, according to a report on the Utah Avalanche Centre's website.
The woman is lucky to be alive and uninjured, said Bruce Tremper, director of the Utah Avalanche Centre. He said Utah averages about four avalanche fatalities a year.
"It's a game of Russian roulette," Mr Tremper said. "People may perceive a slope to be safe, but there are booby traps all around."
The skier's descent into the gully was so steep and short that her air bag had little time to work at keeping her above the snow, but it might have kept her from getting buried longer, and under much deeper snow, officials said.