VERLOT, Wash. (AP) — Search crews have recovered the body of a 13-year-old girl who was killed in an avalanche while hiking in the Cascade Mountains northeast of Seattle.

The girl, whose name was not immediately released, was hiking with a group of six children, ages 12 to 16, and a 45-year-old man, when the avalanche struck Friday afternoon near Mount Pilchuck.

Initially, four children were trapped in the slide. One boy freed himself, and the group rescued two other girls, Snohomish County sheriff's spokeswoman Rebecca Hover told The Herald of Everett.

The group called for help at a nearby visitor's center after spending an hour searching for the 13-year-old girl from Mukilteo, Hover said.

Sheriff's and volunteer mountain rescue teams found her late Friday night and brought her body off the mountain early Saturday.

"As sad as this situation is, as tragic as it is, we were relieved and surprised that we didn't have more fatalities," Hover said.

The group had set out to hike a nearly 3-mile trail to Lake 22 on the north slopes of Mount Pilchuck, about 40 miles northeast of Seattle, but bad weather forced them to turn back before reaching the lake.

Search-and-rescue crews believe the avalanche may have been triggered by the failure of a cornice, a formation of snow that piles high on a peak or ridge, buidling up like a frozen wave.

On Friday afternoon, the weather warmed up and heavy rain fell amid high winds, creating volatile conditions for an avalanche.

Snow slides have killed nine people in Washington state so far this season, a death toll that experts say is the worst in modern history.

Washington state has averaged two to three avalanche deaths in recent winters. The national average is about 25, with the most deaths in Colorado and Alaska, according to the U.S. Forest Service's National Avalanche Center in Ketchum, Idaho.

So far this season, Washington's snowpack is 30% to 60% above normal, and the snow isn't falling in the usual steady pattern that leaves a hard, solid snowpack, said Kenny Kramer, avalanche meteorologist with the Northwest Weather and Avalanche Center.