Survivors Speak: Those who lived through the California avalanche are recounting the final moments of the friends who were with them—a recording just two minutes long, but filled with heartbreak

Truckee, California — Survivors tried to unbury their friends when an avalanche struck a group of backcountry skiers near Lake Tahoe in Northern California earlier this week, according to new harrowing details from a local sheriff’s official.

The avalanche, the deadliest in California history and fourth deadliest in U.S. history, killed at least eight people. A ninth skier is still missing but is presumed dead, officials have said. Rescuers were waiting for the weather to clear before continuing their search. Recovery efforts were halted due to blizzard conditions and an unstable snowpack.

Nevada County Undersheriff Sam Brown told CBS News on Thursday that when the avalanche hit, the skiers “went into, I think, frantic mode of trying to find their friends and partners. And they were ultimately able to unbury three individuals who did not survive.”

Brown described a chaotic scene near Castle Peak, north of the Boreal Mountain Ski Resort, with eight feet of snow and 90 mph winds catching by surprise the 15 skiers who were returning from a three-day guided backcountry trip.

“Uncovering people who are deceased, that they know and probably cared about, is just horrible,” Brown said.

Six of the 15 skiers survived and were rescued. The bodies of eight skiers have been found but because weather conditions were still so bad as of Thursday, they had not yet been recovered. Crews have marked their locations with avalanche poles.

Brown explained Thursday that the initial rescue was remarkably complex because authorities needed standby search and rescue crews for the rescuers themselves.

“We sent two teams in from two directions,” Brown said. “We needed a rescue team for those teams, in the event that an avalanche was triggered.”

A skeleton crew of five rescuers has remained on the mountain since Tuesday, working to carve out a path for additional rescuers, but they have been hampered by the storms blasting the region.

“We’re waiting for the weather and for the avalanche risk,” Brown said.

Authorities are trying to determine why the group continued on its trip even though an avalanche watch was issued for the region on Sunday, two days before the avalanche occurred. An avalanche warning was issued on Tuesday.

The group included four guides from Blackbird Mountain Guides and 11 clients, Blackbird said in a statement Wednesday. Blackbird said all its guides were avalanche safety instructors. Blackbird said that of the six survivors, one was a guide and five were clients.

California’s Division of Occupational Safety and Health told CBS News Sacramento that it was investigating Blackbird.

Brown explained that even experience has its limits.

“Even if you are equipped and have the ability, that doesn’t mean you’re gonna be able to outstand Mother Nature,” Brown said.

The families of six of the victims released a joint statement Thursday saying they are “devastated beyond words” and identifying the victims as Carrie Atkin, Liz Clabaugh, Danielle Keatley, Kate Morse, Caroline Sekar and Kate Vitt.

Vitt, a former SiriusXM executive from the Bay Area, was also identified to CBS News by a family friend.

“It’s a horrible tragedy,” said the friend, who has known the family for 50 years. “She died up in the mountains off of I-80 up there near Sugar Bowl. She and her friends were on a guided overnight backcountry skiing trip.” They asked not to be named out of respect for the family.

Several of those killed were members of the Sugar Bowl Academy, a private school and ski and snowboarding club for those ages 5 to 23, the Academy said in a statement Wednesday.

California Gov. Gavin Newsom said he and his wife, first partner Jennifer Siebel Newsom, were connected to at least some of the victims.

“It turns out (we have) a lot of mutual friends,” Newsom said, without naming anyone directly. “Just learning some of my wife’s old family friends (were involved).”