Updated 10:57 PM ET
SNOQUALMIE PASS, Wash. Rescuers scrambled late Saturday to find a missing snowshoer after a pair of spring avalanches struck separate groups in the mountains east of Seattle, the authorities said.
Three people were initially reported missing, but officials said late Saturday that only one man is now unaccounted for following the twin avalanches.
One avalanche, at Granite Mountain, carried three snowshoers more than 1,200 feet, said Sgt. Katie Larson of the King County Sheriff's Office.
"One of the climbers tells me that they had no warning," she told KOMO-TV. "The avalanche, at this point, from what he's describing, is 30 feet wide, eight feet deep and about a quarter-mile long."
Two men emerged from the snow, but their friend, described as a 60-year-old man, was still missing Saturday evening.
Northwest Weather and Avalanche program director Scott Schell said that the agency's daily bulletin had ranked Saturday's conditions as having a "considerable" danger for avalanches in the area.
The other avalanche occurred on Red Mountain, near the Alpental Ski Area off I-90. A woman was hiking with her dog near a group of a dozen other people when the avalanche hit.
The woman, who had been reported missing, was hypothermic and unable to walk after she was unearthed from several feet of snow. Her dog was OK.
The other person initially reported missing, Chris Soun, told KOMO the group was about 2-and-a-half miles into the wilderness when the avalanche struck and split the group. He said his friends found him buried against a tree and dug him out.
"I thought I was dying,"' Soun said.
Several people in the 12-person party made it off the mountain, but most were still there by 5:30 p.m. None is believed to have a serious injury.
The avalanches occurred as heavy snow fell near Snoqualmie Pass about 50 miles from Seattle.
An avalanche meteorologist with the U.S. Forest Service's Northwest Avalanche Center said April snow is particularly susceptible to avalanches, because of warmer daytime temperatures and more sunshine.
"Spring skiing is a tradition here," Garth Ferber said. "April snowfall is common and susceptible to the effects of sun and daytime heating."