NEVADA CITY, Calif. — In a tragic turn of events, eight backcountry skiers have been confirmed dead, and one remains missing following a devastating avalanche near Castle Peak, close to Lake Tahoe, as reported by the Nevada County Sheriff’s Office on Wednesday.

A group of 15 skiers was caught in the avalanche, but rescue teams managed to save six individuals despite the challenging conditions posed by a snowstorm in the rugged mountainous terrain.

Of those rescued, two were hospitalized; one has since been discharged. Fortunately, their injuries are not considered life-threatening. The survivors include five clients and one guide from the backcountry skiing expedition.

Initial reports mistakenly counted 16 skiers on the trip, but the sheriff’s office clarified on Tuesday night that only 15 were present, as one person had decided not to participate.

Among the missing is a spouse of a member from the Place County search and rescue team, officials revealed on Wednesday.

Search and rescue operations were launched on Tuesday in response to a 911 call reporting an avalanche and people trapped at Frog Lake, located in the Castle Peak area northwest of Lake Tahoe.

According to ABC News, this is the deadliest skiing avalanche in modern U.S. history.

That death toll eclipses the 1982 Alpine Meadows ski area disaster where seven died.

The deadliest avalanche in modern U.S. history (since the recreational era began in 1950) was when 11 climbers were killed on Mt Rainer in 1981.

A three-day ski trip

The skiers were on the last day of a three-day backcountry skiing trek, said Steve Reynaud, a Tahoe National Forest avalanche forecaster with the Sierra Avalanche Center, which had contact with people on the ground in the area. He said the skiers spent two nights at huts on a trip that required navigating “rugged mountainous terrain” for up to 4 miles (6.4 kilometers) while bringing along all food and supplies.

Nevada County Sheriff Capt. Russell Greene said authorities were notified about the avalanche by the ski tour company that led the expedition, Blackbird Mountain Guides, and by emergency beacons the skiers were carrying. Rescuers made their way cautiously toward the scene of the avalanche because of the danger of more avalanches.

Blackbird Mountain Guides said in a statement on its website that it was coordinating with authorities on the rescue operation.

Dangerous backcountry conditions

California is being walloped this week by a powerful winter storm bringing treacherous thunderstorms, high winds and heavy snow in mountain areas.

“It’s particularly dangerous in the backcountry right now just because we’re at the height of the storm,” said Brandon Schwartz, Tahoe National Forest lead avalanche forecaster at the Sierra Avalanche Center, based in Truckee.

The center issued an avalanche warning for the area in the Central Sierra Nevada, including the Greater Lake Tahoe region, starting at 5 a.m. Tuesday with large slides expected into Wednesday.

The town of Soda Springs, near where the avalanche took place, recorded at least 30 inches (76 centimeters) of snow during a 24-hour period, according to the Soda Springs Mountain Resort.

The dangerous conditions were caused by rapidly accumulating snow piling on fragile snowpack layers coupled with gale-force winds.

The storm wreaked havoc on roads from the Sierra Nevada to Sonoma County. Traffic was halted temporarily in both directions on I-80 over and around Donner Summit due to spinouts and crashes, the authorities reported.

Several Tahoe ski resorts were fully or partially closed due to the weather. Resorts along highways have avalanche mitigation programs and were not expected to be at as high of a risk as the backcountry, where travel in, near or below avalanche terrain was strongly discouraged, the center said.

Area has dark history

Castle Peak, a 9,110-foot (2,777-meter) mountain north of Donner Summit, is a popular backcountry skiing destination. The summit, which can be perilous in snow, is named for the infamous Donner Party, a group of pioneers who resorted to cannibalism after getting trapped there in the winter of 1846-1847.

In January, an avalanche in the region buried a snowmobiler in snow and killed him, authorities said. Each winter, 25 to 30 people die in avalanches in the U.S., according to the National Avalanche Center.

Training in avalanche assessment and rescue and safety equipment is highly recommended for backcountry skiing, also known as off-piste skiing, involves venturing deep into the wilderness far outside the confines of a resort. Backcountry skis are wider and heavier and have other features to handle going up and down ungroomed terrain, unlike cross-country skis, which are narrower and designed for flat, more groomed trails.