SANDPOINT — A Sandpoint High School sophomore died following a skiing accident at Schweitzer Mountain Resort on Tuesday.

Schweitzer Mountain and Bonner County Sheriff’s officials withheld the victim’s name, although the teen’s immediate family has been notified.

William Johnson, 15, of Sandpoint, was killed in the accident.

Johnson was discovered unconscious and unresponsive in a tree well by a group of snowboarders, who reported it to Schweitzer Mountain Ski Patrol at about 12:15 p.m., according to a news release issued by the resort.

Schweitzer said patrollers were dispatched to the location, but were unable to find the reporting parties. The search area was expanded and the teen was found at about 12:30 p.m, the resort said.

Patrollers began performing cardiopulmonary resuscitation and Johnson was taken to Schweitzer First Aid. Doctor Ken Gramyk of Bonner General Hospital was on site and pronounced Johnson dead, Schweitzer officials said.

“Our hearts and prayers are with the family during this time as they attempt to cope with this unfortunate situation,” Schweitzer CEO Tom Chasse said in a statement.

The incident is being investigated by the resort and county authorities.

“Early investigation results indicate the victim was involved in an unfortunate skiing accident,” sheriff’s Lt. Doug Harris said in a news release.

An autopsy will be performed at Providence Holy Family Hospital in Spokane, Wash., said Bonner County Coroner Kitt Rose. A cause of death was not released on Tuesday.

“It’s still under investigation,” Rose said.

The location of the tree well Johnson fell into was not disclosed on Tuesday.

The wells are holes that form around the bases of coniferous trees, mainly in ungroomed portions of ski resorts. They form when low-hanging branches keep snow from consolidating around the base of the tree, creating a deep void which can be obscured by branches.

Those who fall into tree wells risk suffocation and or asphyxiation, known in alpine safety jargon as a Non-Avalanche Related Snow Immersion Death.

The odds of surviving deep-snow immersion are not high for those skiing or riding without a partner, according to research conducted by the Northwest Avalanche Institute and the Pacific Northwest Ski Area Association.