Three people are dead and as many as eight missing after an avalanche Sunday near a popular ski resort in Washington state, authorities said.

The King County Sheriff's Office began receiving word about the slide near the Stevens Pass ski area just after noon, Sgt. Cindi West said. Stevens Pass is in the Cascade Mountains northeast of Seattle.

West initially said two people had died but later confirmed there were three deaths.

The deaths occurred in an out-of-bounds area near the resort, she said. Search and rescue crews and other emergency responders were at the scene.

The Northwest Weather and Avalanche Center on Sunday issued a warning for high avalanche danger for areas above 5,000 feet, saying warmer weather could loosen surface snow and trigger a slide on steeper slopes. The elevation of the avalanche wasn't immediately clear.

At mid-afternoon, the temperate at the base of the ski resort was 24 degrees, with light winds and good visibility. The temperature at the top of the mountain was 22 degrees, according to the resort's website.

The site also said Sunday was a "popular powder day" at the resort, with 14 inches of fresh snow falling overnight.

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.

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.

Avalanche deaths are more common in the backcountry than at ski resorts. Out of about 900 avalanche deaths nationwide since the 1950-1951 winter, 32 were within terrain that was open for riding at ski resorts, according to the Utah Avalanche Center.

Also Sunday, West said a snowboarder was killed in a separate incident at the Alpental ski area east of Seattle. The snowboarder went over a cliff. No other details were available.