Eight backcountry skiers were killed and one person is missing after an avalanche near Lake Tahoe, California, authorities said Wednesday. The avalanche was the deadliest avalanche in the United States in more than 40 years.

The victims, including three of the four tour guides, were found fairly close together, said Capt. Russell Green of the Nevada County Sheriff’s Office. A fourth guide was among the survivors.

The dead and missing include seven women and two men between the ages of 30 and 55. Due to the harsh conditions, crews have not yet been able to remove the victims from the mountain.

The sheriff’s office announced the same day that crews’ efforts had shifted from rescue to recovery.

Six others from the same group of skiers were rescued on Tuesday, one of whom remained in the hospital on Wednesday. They were on a three-day guided trek through Northern California’s Sierra Nevada Mountains as a monster winter storm battered the West Coast.

“Someone saw the avalanche, yelled avalanche, and the avalanche quickly overtook them,” said Capt. Russell Green of the sheriff’s office.

The avalanche was the deadliest avalanche in the United States since 1981, when 11 climbers died on Mount Rainier in Washington state.

Crews have faced dangerous situations since then The avalanche occurred on Tuesday morning.. Search and rescue teams were called to the Castle Peak area of ​​the Sierra Nevada after reports of 15 skiers buried in an avalanche.

Two of the people rescued after several hours of searching were taken to a hospital for treatment, Nevada County Sheriff’s Office spokeswoman Ashley Cuadros said. Heavy snow and the threat of more avalanches delayed rescue efforts in the mountains near Castle Peak northwest of Lake Tahoe.

Avalanche danger remains high

Castle Peak is a 2,777-meter mountain north of Donner Summit, a popular backcountry ski area. This snowy and treacherous summit is named after the Donner Party, a notorious group of pioneers who resorted to cannibalism after being trapped in the winter of 1846-1847.

The summit area is one of the snowiest in the Western Hemisphere, and until just a few years ago it was closed to the public. The Truckee Donner Land Trust, which owns the cabins where the group was staying near Frog Lake, says it averages nearly 30 feet of snow a year.

The Sierra Avalanche Center warned Wednesday that avalanche danger remains high and advised against travel to the area. The center said several meters of snow and strong winds in recent days have made the snowpack unstable and unpredictable, and more snow is predicted to fall.

Green, along with the sheriff’s office, said authorities were alerted to the avalanche by Blackbird Mountain Guides, who was leading the expedition, and the skier’s emergency beacon. The agency announced Tuesday night that 15 backcountry skiers were on the trip, not 16 as originally believed.

Steve Raynaud, an avalanche forecaster with the Sierra Avalanche Center, said the skiers were on the last day of a backcountry ski trip and were staying in a cabin for two nights. He said the area requires navigating through rugged mountainous terrain. All food and supplies must be carried to the hut.

Reaching the cabin in the winter takes several hours and requires backcountry skills, avalanche training and safety gear, the Land Trust says on its website.

Blackbird Mountain Guides said in a statement that the group was returning to the trailhead when the avalanche occurred.

“Our thoughts are with the missing persons, their families, and the first responders on the scene,” Blackbird said in a statement Wednesday. The company said it was assisting authorities with their investigation.

Several ski resorts in Tahoe were fully or partially closed due to the weather. The center said resorts use controlled explosions and fencing to deal with avalanche threats, but were not expected to be at as high a risk as the backcountry.

In January, an avalanche in the area buried and killed a snowmobiler, authorities said. According to the National Avalanche Center, 25 to 30 people die in avalanches each winter in the United States.