Eight backcountry skiers have been confirmed dead and one person remains missing after a powerful avalanche swept through a guided expedition in California’s Sierra Nevada near Lake Tahoe, authorities said, marking the deadliest avalanche disaster in the United States in more than four decades.
Nevada County Sheriff Shannan Moon said families had been notified and officials had transitioned operations from rescue to recovery, reflecting the grim scale of the tragedy. The disaster has deeply shaken the close-knit backcountry skiing community as well as rescue teams who worked in dangerous weather conditions to reach the remote mountain site. Officials noted that the incident is the deadliest avalanche in the country since a 1981 Mount Rainier disaster that killed 11 climbers.
The avalanche struck Tuesday morning in the Castle Peak area near Donner Summit, north of Interstate 80, after an intense winter storm blanketed the region with heavy snowfall. Emergency services received a 911 call reporting that as many as 15 skiers had been buried beneath the snow. Six members of the group were later found alive after hours of searching, with two transported to hospital for treatment, while crews continued efforts to locate the final missing skier.
Rescue operations have been slowed by severe conditions, including heavy snow, strong winds and the continued threat of additional avalanches. Forecasters warned that the snowpack remains highly unstable following several feet of fresh accumulation combined with gale-force winds, and further snowfall is expected to worsen risks in the coming days. Authorities said rescuers were alerted both by the guiding company leading the expedition and by emergency locator beacons carried by participants.
The group had been taking part in a three-day guided backcountry skiing trip near Frog Lake, staying in remote huts operated by the Truckee Donner Land Trust. The expedition, organised by Blackbird Mountain Guides, included experienced skiers accompanied by professional guides. The avalanche struck as the party was making its return toward the trailhead on the final day of the journey through rugged terrain that requires specialised training and equipment.
Donner Summit is among the snowiest regions in the western hemisphere, receiving an average of about 35 feet of snow each year. While its steep slopes attract advanced backcountry skiers, the same conditions also make the area particularly vulnerable to avalanches, especially during powerful winter storms. Unlike managed ski resorts, which actively control snowpack using explosives and safety barriers, backcountry terrain remains largely uncontrolled and significantly more dangerous.
Avalanche experts have urged the public to avoid travel in high-risk mountain areas, warning that current conditions remain unpredictable. Nationwide, avalanches typically claim between 25 and 30 lives each winter, according to the National Avalanche Center. The Donner Summit region has seen similar incidents in the past, including a fatal avalanche involving a snowmobiler earlier this year, and carries historical significance as the site where the Donner Party became stranded during the winter of 1846–47.
