Six backcountry skiers were found alive Tuesday after an avalanche in the Castle Peak area of Northern California, while 10 others remained missing.

The group included four ski guides and 12 clients, and survivors were instructed to shelter in place until search and rescue teams could reach them.

The avalanche occurred amid a powerful winter storm bringing heavy snow, high winds, and thunderstorms to the Sierra Nevada, creating high avalanche danger in the backcountry.

Authorities deployed 46 emergency responders from the Nevada County Sheriff’s Office and the California Department of Forestry and Fire Protection to assist in the rescue, PBS.org has reported.

The storm also forced closures at several Lake Tahoe ski resorts and caused hazardous conditions on roadways, with forecasts warning of up to 8 feet of snow in parts of Northern California.