All nine victims of February’s deadly avalanche near Lake Tahoe died from suffocation after being trapped under roughly five to six feet of snow, officials confirmed this week.
The update came as the Nevada County Sheriff’s Office announced it had completed its investigation into whether criminal negligence played a role in the tragedy, forwarding the case file to county prosecutors for further review.
The avalanche hit on Feb. 17 near Castle Peak, sweeping through a 15-person backcountry skiing group during one of the most powerful blizzards the region had seen in years.
The group was affiliated with Blackbird Mountain Guides and included six clients and three guides who were killed. Five others — one guide and four clients — survived.
Earlier that day, avalanche forecasters had issued an unusually stark advisory, urging people to avoid the backcountry because conditions had become extremely dangerous.
Even with those warnings in place, the Blackbird party moved near Perry’s Peak, where heavy, fast-accumulating snow had created an unstable and hazardous slope.
A slab of snow about 100 feet wide suddenly released and thundered approximately 400 feet downhill, engulfing nearly the entire group and leaving only two people unburied.
The survivors immediately began digging frantically through the avalanche debris in an effort to reach those trapped beneath the snow.
They managed to rescue four companions before deciding they could no longer reach the others.
As the blizzard worsened, they turned their attention to keeping themselves and two injured skiers alive.
An incident report published by the Sierra Avalanche Center, which had issued the avalanche warning, found that the group violated avalanche protocols during its attempt to leave the backcountry.
The first search-and-rescue crews reached the scene around 5:36 p.m., after authorities received word of the avalanche at about 11:30 a.m.
Rescuers dug out eight of the nine victims that day.
But with heavy snow hammering the area, they eventually placed the bodies together beneath a tarp, recorded their location with GPS coordinates and marked the spot with long poles used to search for avalanche victims.
The crews finished around 10 p.m.
The blizzard then prevented further recovery efforts for two days.
On Feb. 20, teams returned to the avalanche site, recovered the eight bodies and located the ninth victim.
All nine were airlifted to Frog Lake Huts, the backcountry lodging where the group had stayed for two nights before the avalanche.
The bodies were then transported out by snowcat and taken to a mortuary in Truckee.
Partially redacted coroner’s reports released Thursday list asphyxiation caused by snow burial as the cause of death for all nine victims.
Sections describing the condition of the bodies were redacted.
The sheriff’s findings now sit with prosecutors.
A prosecutorial review is the normal next step in a criminal investigation and does not necessarily mean charges will be filed.