Months after a catastrophic avalanche claimed nine lives near Lake Tahoe, authorities have confirmed that all nine victims died from asphyxiation after being buried beneath several feet of snow.

The revelation came as the Nevada County Sheriff’s Office completed its investigation into the February disaster and forwarded its findings to the county prosecutor for review.

The avalanche struck on February 17 as a 15-member backcountry group traveled near Castle Peak during an intense winter storm.

The group included six clients and three guides from Blackbird Mountain Guides, along with four additional clients and one guide. Nine people ultimately lost their lives, while six others survived.

Before the avalanche, forecasters had issued a serious warning about extremely dangerous avalanche conditions and urged people to avoid backcountry travel.

Despite the warning, the group moved near Perry’s Peak, where unstable snow had accumulated on the slope.

A section of snow approximately 100 feet wide broke loose and swept roughly 400 feet down the mountain, burying most of the group.

Survivors immediately began digging through the debris in an attempt to rescue their companions. Four people were recovered alive, but worsening weather and difficult conditions eventually made it impossible to reach everyone who remained buried.

Rescuers first arrived at the scene at approximately 5:36 p.m., several hours after authorities were alerted to the avalanche.

Eight victims were recovered that day. However, the continuing blizzard forced rescue teams to suspend operations overnight. The bodies were temporarily secured at the scene, with their locations recorded and marked for later recovery.

Two days later, on February 20, rescue crews returned to the avalanche site. They recovered the eight victims and located the ninth.

All nine victims were eventually transported from the remote area to Frog Lake Huts, where the group had been staying before the disaster. Their remains were later taken by snowcat to a mortuary in Truckee.

Partially redacted coroner’s reports released this week identified snow burial and resulting asphyxiation as the cause of death for all nine victims.

The reports did not publicly disclose every detail concerning the condition of the victims, with portions remaining redacted.

An incident report from the Sierra Avalanche Center also found that the group violated established avalanche safety protocols while attempting to leave the backcountry.

The sheriff’s investigation has now been completed, but the case is not necessarily over. Prosecutors will review the findings to determine whether any criminal charges are warranted.

A prosecutorial review is a standard step following a criminal investigation and does not itself mean that charges will be filed.

For the families and friends of the nine victims, the conclusion provides an official account of how the tragedy unfolded, but it cannot undo the loss caused by one of the region’s most devastating avalanche disasters in recent years.