More than 150 rescue workers and trained dogs began scaling Utah's treacherous backcountry at sunrise Sunday to continue the search for as many as five people feared buried by a massive avalanche.

The amount of snow forced down the mountain by Friday's slide — up to 30 feet deep at some points — has forced authorities to count the potential victims by matching eyewitness accounts of the avalanche to a list of skiers thought to be in the area at the time.

One person has been identified as having been consumed by the avalanche: Shane Maxiner (search), 28, of Sandpoint, Idaho, whose friend told a 911 dispatcher that he saw Maxiner buried by the slide, Summit County Sheriff Dave Edmunds said.

Rescue workers spent all day Saturday digging through a massive snow pile but found no traces of any of the missing. If a second sweep of the debris field fails to find anything Sunday, authorities will bring in machines to take away layers of snow, Edmunds said.

Those feared buried were in an out-of-bounds area near The Canyons (search) resort that had been marked with a skull and crossbones warning to thrill-seekers. Adding to the danger were two weeks of wet, heavy snow across the Wasatch mountain range that prompted extreme avalanche warnings across the region but especially in the backcountry.

The danger of more avalanches remained high in the Wasatch Mountains, which received as much as eight feet of wet, heavy snow over the last two weeks.

Volunteers are "risking their lives trying to make a recovery," Edmunds said.

"It's very frustrating because these kids should not have been in that area. This was an area that was roped off and signed, and they just chose to ignore it," the sheriff said.

Six people have already been killed in Utah avalanches this winter and it's still relatively early in the season. The total is the highest since the state began keeping records of avalanche deaths in 1951.