(CNN) -- Three people were killed Sunday in an avalanche near a ski resort in Washington state, officials with the King County Sheriff's Office said.
Spokeswoman Katie Larson said several groups of skiers were caught in the deadly rush.
"Almost all of them -- probably up to 12 at some point -- are buried in the snow. They manage to dig themselves out. ... At that point then, they look and they find that three of these skiers are suffering from medical issues. They begin CPR and, unfortunately, they were not able to resuscitate the victims," she said, adding that everyone was accounted for.
All the skiers were experienced and had the appropriate equipment, Larson said. "Nature happened."
Several were swept as far as 1,500 to 2,000 feet down, said Deputy Chris Bedker of the King County Sheriff's Office. All had avalanche beacons, and one wore an avalanche rescue system, which works like an airbag and helped her to survive, he said.
The skiers were in a designated out-of-bounds area, but it was not closed and they were allowed to be there, Bedker said.
John Gifford, general manager of the Stevens Pass ski area in the Cascade Mountains, said the avalanche took place roughly three miles west of the resort. Operations were not affected.
Heavy snow has hit the region recently. A post on the resort's website Sunday reported that more than 2 feet of snow fell overnight Saturday.
The Northwest Weather and Avalanche Center forecast the area as having a high avalanche danger Sunday, Bedker said.
"The skiers were aware of that. ... They took that risk," he added.
In a separate incident Sunday, a snowboarder was found dead near Snoqualmie Pass in the same mountain range. The cause of death was not immediately known.
CNN's Dave Alsup contributed to this report.