An avalanche buried a snowmobiler Monday in Utah's Wasatch County as forecasters warned outdoor enthusiasts that conditions will be dangerous through New Year's Day.

"I want to caution people to play it conservative, especially in the western Uinta Mountains," said Bruce Tremper, director of the Utah Avalanche Center.

Rescuers rushed to save a snowmobiler who was swept away by an avalanche near a trailhead east of Heber City. He was found and taken to Utah Valley Regional Medical Center in Provo.

"I don't know his condition," said Kim Butler of the Wasatch County sheriff's office.

Two men have died in Utah avalanches since Dec. 23. Thousands of people on skis, snowshoes or snowmobiles are expected to hit the Utah backcountry Tuesday.

For the western Uintas, about 35 miles east of Salt Lake City, Tremper issued a special warning — just one notch below "extreme."

He rated the more accessible Wasatch Range only slightly less dangerous after 2 feet of fresh snow.

The Uinta snowpack suffers from a layer of loose, sugary snow that fell in October and was glazed by a November dry spell. On top of that is several feet of new snow bearing down.

"It's like putting a brick over a pile of potato chips," Tremper said. "It just won't support much weight."

Backcountry travelers were urged to avoid all open slopes in the Uintas, especially terrain facing the northeast above 9,500 feet.

That was the setting when Dave Balls, a 53-year-old snowmobiler from Oakley, died on Christmas in a 4-foot-deep, 1,000-foot-wide avalanche off the summit of 11,000-foot Windy Peak.

More unusual was the death of a 30-year-old Colorado skier during an avalanche at The Canyons resort in Park City on Dec. 23. Jesse Williams died of head trauma after hitting a tree.

An avalanche inside a ski area, where patrollers routinely set off explosives to keep the slopes safe, is extremely unusual, Tremper said.

"I've never heard of anything like that before," he said.

The same slide buried an 11-year-old boy for 30 minutes. Max Zilvitis remembered to create an air pocket while he was engulfed in several feet of roiling snow. He woke up at a hospital the next day, apparently no worse for the wear.

As always, backcountry skiers were urged to carry an avalanche beacon and collapsable shovel and probe. In groups, skiers should expose only one person at a time to crossing an open slope, Tremper said.

"We estimate as many people disperse throughout the backcountry of Utah as at any individual resort. That could be thousands of people, including people walking their dogs," Tremper said. "The backcountry is a very popular place."

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