An avalanche in California's Lake Tahoe region has left 10 backcountry skiers missing, while six others are stranded and awaiting rescue. The Nevada County Sheriff's Office reported the avalanche around 11:30 PST in the Castle Peak area near Truckee. The group included four guides and 12 clients. Weather conditions remain harsh, with a high risk of more avalanches. "Highly-skilled rescue ski teams" have been sent from two nearby ski resorts, the sheriff said. The six survivors have been "directed to shelter in place as best they can in the conditions," the sheriff added. On Facebook, the sheriff posted: "At least six of the skiers have survived the avalanche and remain at the avalanche site, awaiting rescue, with the remaining ten unaccounted for." Rescue operations involve 46 emergency responders, including a SnoCat team that moves on snow using treads. Experts from Boreal Mountain Ski Resort and Alder Creek Adventure Center are also trying to reach the site. The Sierra Avalanche Center warned that "large avalanches are expected to occur Tuesday, Tuesday night, and into at least early Wednesday morning across backcountry terrain." They rated the avalanche danger as "high," a level four out of five. The center advised against travel in or near avalanche terrain, stating: "A widespread natural avalanche cycle is expected over the next 24 hours." Boreal Mountain Ski Resort, close to the accident site, reported 30 inches of snowfall in the last 24 hours. Due to heavy snow, high winds, and low visibility, the resort closed on Tuesday. The storm also shut several highways, including Interstate 80 and Highway 50.