A Christmas Day snowmobiling trip turned tragic when a Utah man was killed in an avalanche at the top of Weber Canyon.

A group of people were taking a holiday ride at the popular snowmobiling area Thousand Peaks about 2:30 p.m. Tuesday when an avalanche was triggered, burying and killing the man, Summit County Sheriff's Sgt. Kris Hendricksen said.

"We don't know if it was triggered by the snowmobilers or if it was just bad timing for the snowmobilers to be where they were," Hendricksen said.

The man was riding with about five other snowmobilers in an area of Thousand Peaks known as the Super Bowl. The man, whose name was not released as of Tuesday night, was the only member of the group caught in the slide.

The size of the avalanche was unknown Tuesday night, though Hendricksen described it as "fairly large."

Other snowmobilers in the man's party were well-prepared and equipped with shovels, he said, and attempted to dig the man out.

"They had equipment, but they were unable to extract him," Hendricksen said.

The man was buried for "several hours" before Summit County search-and-rescue crews were able to reach him, he said.

Paramedics were not able to determine at the scene if the man was still alive, so life-saving measures were taken and he was flown to Heber Valley Medical Center, Hendricksen said. He was pronounced dead at the hospital.

Sheriff's officials met Tuesday night with family members of the deceased man, who owns a cabin in Summit County, Hendricksen said.

It was the second deadly avalanche in Summit County in three days. Jesse R. Williams, 30, of Grand Junction, Colo., was caught in a slide and killed Sunday at The Canyons ski resort.

An 11-year-old boy also was caught in the avalanche and buried for 33 minutes. He was taken to Primary Children's Medical Center, where as of Monday he had not regained consciousness and was listed in critical but stable condition.

The lack of cell service in the area of Tuesday's avalanche was making it difficult for Summit County search-and-rescue crews to provide information to sheriff's officials not on the mountain, Hendricksen said.

Thousand Peaks, located at the end of Weber Canyon Road, boasts more than 60,000 acres of backcountry for snowmobiling.

E-mail: jpage@desnews.com