10 people missing in Tahoe avalanche, sheriff's officials say

TRUCKEE, Calif. - Search and rescue teams with the Nevada County Sheriff's Office were responding to an avalanche on Tuesday with 10 people unaccounted for, off Interstate 80 near Donner Summit and Truckee.

What we know:

The sheriff's office said that the report came in at about 11:30 a.m., in the Castle Peak area, with a group of 16 people initially in danger. 

"At least six of the skiers have survived the avalanche and remain at the avalanche site, awaiting rescue, with the remaining ten unaccounted for," sheriff's officials shared on Facebook in an update on the situation late Tuesday afternoon. Officials said the group was made up of four ski guides with 12 clients.

Rescue efforts underway

The sheriff's office said that a large multipronged effort was underway in response to this emergency, from ski rescue crews to a snowcat team to maneuver through the heavy snow.

Dozens of first responders were also on scene, sheriff's officials said, as they stressed the perilous conditions that persisted in the area.  

"Rescue efforts remain in progress now with 46 emergency first responders. Weather conditions remain highly dangerous," officials said. 

What to know about the skiers

The group of 16 skiers were on the last day of a three-day backcountry skiing trip, Steve Reynaud, a Tahoe National Forest avalanche forecaster with the Sierra Avalanche Center, told the Associated Press.

Reynaud said the skiers had spent two nights in huts on a trip that required navigating "rugged mountainous terrain" on backcountry skis for up to four miles and bringing along all food and supplies.
 

Big picture view:

The region is under an avalanche warning as the Sierra gets pummeled by a powerful storm. 

The UC Berkeley Central Sierra Snow Lab said the area was being hit with the worst winter conditions in three years, with more than 5 feet of snow expected in a matter of days.

The avalanche warning is in effect through Wednesday morning at 4 a.m.

Sierra Avalanche Center, which works in partnership with the U.S. Forest Service, rated the danger at "high," or level 4 out of a scale of 5. 

Brandon Schwartz, lead and director of the center, said he was in that area on Monday when the level was at 3, to survey the conditions.

"It's ongoing storms, high intensity snowfall," Schwartz said. "There's low visibility and there's unstable snowpack and there are avalanches happening."

He said that the area is known as a popular spot for skiers and snowmobilers. 

"The area where this avalanche occurred today with these a person's involvement Is not far from the Frog Lake area where there is a backcountry hut that people will ski into and spend the night and then skiing themselves out of," Schwartz noted.

SEE ALSO: Bay Area storm timeline: Coldest system of the season sweeps through

Dig deeper:

Last month, an avalanche in the same area of Truckee led to the death of a man on a snowmobile. He was found buried under snow. 

"The vast majority of avalanches happen either during or in the days following a storm. And that's the case with both of these," Schwartz explained. "The one in early January was at the very end of that January storm cycle, and this one's happening during this February storm cycle. And we haven't had many storms this season that have produced snowfall the way that that storm in January did, and now this one in February," the expert added.

He said the search and rescue teams faced difficulties and dangers as they worked to locate the missing. 

"There can be a lot of snow in this area, definitely going to be challenging to get to," Schwartz said, "and it will have ongoing danger from avalanches in that terrain."