Stevens Pass (Courtesy of Creative Commons)

The avalanche occurred on Stevens Pass in the Cascade Mountains northeast of Seattle.  TIME reported that the deaths occurred "in an out-of-bounds area" near a popular ski resort.

According to The Associated Press and USA Today, those killed were experienced skiers and all others who were initially missing have now been found:

• All were buried to some extent, but the men who died were swept about 1,500 feet down a chute in the Tunnel Creek Canyon area, King County Sheriff's Sgt. Katie Larson said.
• Most of the other skiers, all well-equipped, were able to free themselves and rushed to dig out the victims. They performed CPR on the three men to no avail, Larson said.
• The fourth skier who was swept far down the mountain, a woman, appeared to avoid a similar fate because of the avalanche safety device she was wearing, Larson said. Larson didn't immediately have other details about the device.

TIME also reported that this winter has been a particularly dangerous one in the Washington mountains:

• Four people disappeared in vicious storms while hiking and climbing on Mount Rainier last month.  (They remain missing).
• Across the West, there had been 13 avalanche deaths this season as of Feb. 16, according to the Colorado Avalanche Information Center, which tracks avalanche deaths in the U.S.