And in a separate incident, a snowboarder was killed Sunday at Alpental on Snoqualmie Pass after an avalanche there swept him over a cliff.
The Stevens Pass avalanche came rumbling down the mountainside at about 12:30 p.m. in a back country area where 12 people were skiing in three groups, emergency officials said.
Three men and a woman were caught in the cascading snow slide, which tumbled them 1,500 feet down a chute in the Tunnel Creek Canyon area, King County Sheriff's Sgt. Katie Larson said.
The three men were buried under the snow and died, but the woman survived because she had a survival device, known as an air bag, that kept her near the surface.
ESPN identified the men who were killed as Freeskiing World Tour head judge Jim Jack, Stevens Pass Director of Marketing Chris Rudolph and skier John Brenan.
According to ESPN, the woman who survived is pro skier Elyse Saugstad, who was there with a group of visiting and local skiers, including ESPN's freeskiing editor Megan Michelson, who was unhurt.
When she came to rest, "I was completely buried except for my head and hands," Saugstad told ESPN.
Larson said the three men who died were experienced back-country skiers, aged 30, 35 and 45, who had been in the area before. Other skiers in the area attempted a rescue, but by the time rescuers reached them, the three could not be saved.
"At that point, (rescuers) look and they find that three of these skiers are suffering from medical issues. They began CPR and, unfortunately, they were not able to resuscitate the victims," Larson said.
ESPN reported that two of the men who died were found not far from Saugstad. One was a few feet from her and the other was approximately 50 feet away.
The third deceased skier was carried "several hundred feet" farther down the mountain, Saugstad told ESPN.
Eight other skiers also were caught up in the avalanche, and were initially reported as missing. But they were able to free themselves and call for help, Larson said.
Larson said it was not clear whether the skiers triggered the avalanche. But ESPN reported that the slide was caused by one of the skiers who perished.
They were in a back country area, considered "ski at your own risk," that was blocked off but not closed.
All of the skiers in the three groups were said to be experienced, and all had appropriate gear, Larson said.
The avalanche took place near Highway 2, the Washington State Patrol reported. The highway remains open at this time.
The deadly incidents happened a day after a winter storm dumped heavy snowfall in the mountains.
According to automated data from the Northwest Weather and Avalanche Center, the Stevens Pass ski resort area picked up 24 inches of snow from 5 p.m. Friday through 4 p.m. Sunday. The Stevens Pass highway picked up 28 inches in the same period, and Snoqualmie Pass received 30 inches.
A warning for high avalanche danger was issued Sunday for areas above 5,000 feet.
Stevens Pass, an 80-mile drive from Seattle, is one of the most popular outdoor recreation areas in the state. People flock there to go cross-country, back-country and downhill skiing, as well as snowshoeing and backpacking.
It's been a deadly winter in Washington's mountains. Four people disappeared in vicious storms while hiking and climbing on Mount Rainier last month.
The snowboarder who died at Alpental on Sunday got caught in a separate avalanche at about 11:45 a.m. that pushed him over a cliff, according to several witnesses who saw it happen.
The King County Sheriff's Office said he was a young man in his 20s who was outside the groomed ski areas.
A rescue team found his body a short time later. They performed CPR, but the man died at the scene.
Sgt. Cindi West, King County Sheriff's Office says authorities are urging people to stay inside the designated ski areas - especially times like this when there has been a lot of snow and avalanche warnings are posted.