Wyoming ? A mile-long avalanche near the Wyoming-Idaho state line swept three snowmobilers to their deaths, authorities said Saturday.

Lincoln County officials said the three victims were among four snowmobilers caught by the snow slide Friday near Alpine Mountain in the Snake River Range. Sgt. Shane Tindall said the fourth person walked out and used his cell phone to call for help.

The survivor, 53-year-old Wade Clark of Soda Springs, Idaho, told authorities that the snowmobilers had dropped off a ridge line and into a draw when they saw the snow slab breaking away. The slide was about 100 yards wide and a mile long.

“They tried to outrun it and they didn’t make it,” Tindall said.

He said relatively warm temperatures and sunny skies warmed the rocks and melted snow on the south-facing slope. The avalanche danger was listed as moderate when the slide occurred.