Dangerous conditions delay the recovery of 8 killed in California avalanche

But what the guides and their tour company knew about the warnings and risks from a powerful winter storm that blasted the mountains during the trip and why they pressed on is now part of investigations into the avalanche Tuesday that killed eight people. Six survived the disaster.

It will be at least another day before crews can attempt to recover the bodies and continue the search for a ninth person still missing and presumed dead, said Ashley Quadros, a spokesperson for the Nevada County Sheriff's Office.

"We are on the mountain, but they are not going to be able to safely reach them," she said Thursday. "The weather conditions are really dangerous."

Several more feet of snow could fall around Lake Tahoe on Thursday and continue to destabilize the fragile snowpack, according to the Sierra Avalanche Center. It said that wind gusts along the ridgetops could reach 60 mph (100 kph) and warned there's a high risk of large avalanches through at least Friday morning.

Officials have not yet released the names of those who were killed.

Avalanche victims were from a 'connected community'

The 15 skiers, most of them women, began their three-day trip on Sunday just as warnings about the storm were intensifying. They spent the weekend staying along Frog Lake in high country huts accessible only by challenging trails.

Some have ties with the elite Sugar Bowl Academy, which issued a statement late Wednesday mourning the loss of skiers with "strong connections to Sugar Bowl, Donner Summit and the backcountry community."

Perched on Donner Summit, the academy is a private boarding and day school for competitive skiers and snowboarders. Its former students include multiple Olympians.

"We are an incredibly close and connected community," Sugar Bowl Academy executive director Stephen McMahon said in the statement. "This tragedy has affected each and every one of us."

Tour company says guides were highly experienced

The four guides were employed by Blackbird Mountain Guides, which offers mountaineering and backcountry ski trips as well as safety courses across the West and internationally. One of them was among the six survivors.

Blackbird's website says the tour is intended for intermediate to expert skiers. The company said in a statement it has launched an investigation and paused field operations at least through the weekend while it prioritizes supporting the victims' families.

The guides who led the group were trained or certified in backcountry skiing, and instructors with the American Institute for Avalanche Research and Education. While in the field, they "are in communication with senior guides at our base, to discuss conditions and routing based upon conditions," founder Zeb Blais said in the statement.

"We don't have all the answers yet, and it may be some time before we do," the company said, asking people to refrain from speculating while it reviews what happened.

"This was an enormous tragedy, and the saddest event our team has ever experienced. In addition to mourning the loss of six clients, we also mourn the loss of three highly experienced members of our guide team," Blais said. "We are doing what we can to support the families who lost so much."

Questions linger about why the trip continued during storm

Nevada County Sheriff Shannan Moon said authorities will investigate why the guides proceeded with the tour despite the forecast. The Sierra Avalanche Center had issued an avalanche watch Sunday morning indicating that large avalanches were likely in the next 24 to 48 hours.

Mayor Max Perrey of Marin County's Mill Valley, a city just north of San Francisco, confirmed that some in the group were mothers from his city. He was not able to provide additional details but told The Associated Press via email that more information would be released later.

One of the victims was married to a member of a backcountry search and rescue team in the area, said Placer County Sheriff Wayne Woo.

Authorities said the six survivors scoured the snow for the missing, finding three of the dead while they waited six hours Tuesday for help to arrive in blizzard conditions. One of those rescued was still hospitalized Wednesday, Moon said.

The skiers all had beacons that can send signals to rescuers, and at least one guide was able to send text messages.

The avalanche is the deadliest in the U.S. since 1981, when 11 climbers were killed on Mount Rainier in Washington state.