Rescuers had to hike in and rescue the man by ground overnight, because adverse weather conditions prevented a helicopter rescue.
The 42-year-old skier reportedly suffered two broken legs, possible internal injuries and hypothermia in the backcountry near Alpental.
Doug Caley of Seattle Mountain Rescue said his team's first priority was getting the 42-year-old victim warmed up, because he had been lying in the cold for a long time before rescuers reached him. They then tended to his injuries and brought him out.
The avalanche was reported near Alpental, which includes expert backcountry terrain and is part of The Summit at Snoqualmie, a ski area east of Seattle. The area is popular with extreme skiers.