"It's unbelievable - four tough nights in the teens with no food, no water, just normal ski gear and a helmet," said King County Sheriff's Lt. Jim Fuda.
Dan Witkowski was "lucid and talking," Fuda said Sunday night.
He told Fuda that he got turned around while skiing Wednesday, so decided to head downhill in hopes of finding his way out.
So for four days, he kept moving, resting in the dips of snow surrounding tree trunks to get out of the wind. He told Fuda his longest break was two hours.
"He's whupped," Fuda said.
Witkowski was listed in serious condition early Monday at Harborview Medical Center.
"Everybody prayed in the whole world for my son, and prayer does work," Maryann Witkowski, the skier's mother, told The Seattle Times.
"It was like turning a page in a book and you didn't know there was another page left," his father, Robert Witkowski, 57, municipal director of community development in Ellensburg told The Times. "I'm not sure they got the words invented yet."
Scores of people had been looking for the Ellensburg resident since he was reported missing Thursday. Witkowski had failed to meet up with friends on New Year's Eve and his car was found parked at the Alpental ski area in Snoqualmie Pass, off Interstate 90 about 40 miles east of Seattle.
About a foot of snow fell in the area on Saturday, and searchers feared that if they didn't find him in the clear daylight Sunday, they might not find him at all. A bad storm was expected Monday.
Temperatures in the central Cascades had dropped way below freezing, with a low of zero degrees reported Saturday night at nearby Stampede Pass. Alpental reported 8 degrees Sunday.
The sheriff's office sent up three helicopters Sunday with spotters on board who were familiar with the terrain. Northwest of the ski area, they recognized intermittent ski and boot tracks in the new snow.
A team of six rescuers on skis set out for the area, but because they had to hike over much of the terrain, it took them more than seven hours. They reached Witkowski as dusk fell after 4 p.m. Fuda did not know how far they had traveled.
The helicopters might never have flown over the area had not two independent witnesses come forward to say they had seen someone matching Witkowski's description heading northwest out-of-bounds last Wednesday.
"Neither of those guys watched the news or knew anybody was missing," Fuda said. "Early this morning we knew we had one last day to search, since the weather's supposed to turn again tomorrow, and we just searched the best we could and sent the helicopters up there."
When the rescuers found Witkowski, they called a military helicopter to pluck him from the slopes and take him to Harborview.