TRUCKEE, Calif. – On March 31, the Sierra Avalanche Center posted a final in-depth report of the deadly Feb. 17 avalanche near Castle Peak.

The report provides a narrative of the day’s events, based on two survivors’ accounts from a New York Times article. These two survivors were reportedly located near the back of the group and not involved in route planning or decision-making.

The narrative reveals how a ski binding issue caused a client and a guide to fall behind the main group. These two individuals eventually caught up to find a berm of avalanche debris over their group’s skin tracks.

According to the account, another client, who was with the main group, heard a guide yell “avalanche.” The client then looked up to see a “wall of white with strange blurs of colors.” The report says he realized the colors were tumbling skis and clothing of other skiers. The client dove behind a dead tree at the alert and became buried by debris, but was able to force himself up.

The report goes through these three initial survivors’ next steps, which included transeiver searches and responding to a ski pole that was sticking up and moving. Their actions allowed them to find another three survivors and uncover two deceased members.

The report also breaks down the weather and snowpack around the time of the avalanche, pointing to significant snowfall and wind loading as factors on the sparsely treed slope where the slide occurred. The winds had redistributed the heavy snowfall, the report states, “piling it into drifts far deeper than the amount measured at nearby weather stations.”

As reflected in prior reports, this final report continued to state that many details about the avalanche itself remain unknown because it occurred during a heavy snowstorm. Search and rescue responders reported approximately two feet of new snow on top of avalanche debris when they arrived around 5:30 p.m. and could not obtain a visual of the avalanche crown due to the conditions.

Responders could only determine the edges and toes of the debris field by how far they sank into the snow. On the debris, rescuers could stand and move around in boots, while off the edge of the debris, rescuers reported sinking over waist-deep into the snow.

The end of the report offers comments based on the findings to help avoid incidents like this deadly avalanche in the future. The report says that two of four of the buried survivors required rescue from their companions due to the snow covering their airways.

“The rapid location and excavation of these two individuals was lifesaving,” the report states.

In addition to avalanche details, the report also states that many details regarding human factors, decision making, and travel plans are still unknown, but points out, “This group traveled below avalanche terrain and through the runout zone of an avalanche path during a period when a natural or human triggered avalanche was likely to very likely.”

The report’s comments section also informs that exposing only one person at a time to avalanche terrain is an accepted best practice for backcountry travel. It notes that this group consisted of 15 people and that analysis of past avalanche accidents indicates that larger groups (4 or more people) have a higher chance of being caught in avalanches.

The report provided new details about the ski group, revealing it comprised two separate guided groups that combined on the morning of the avalanche for the return journey to the trailhead. One group consisted of eight females and two guides, and the other consisted of three males and two guides. The guides were all from the same service, Blackbird Mountain Guides.

Read the full report at avalanche.org/avalanche-accidents/#/report/cc583756-68b3-4e06-9fa9-769af352fc18.