Six people, including two guides, are missing on Liberty Ridge on Mount Rainier.
Mount Rainier National Park spokeswoman Patti Wold said Liberty Ridge is one of the more technical and advanced routes on the mountain.
Wold said two guides with Alpine Ascents International and four clients were reported missing Friday at about 4:30 p.m.
Patti Wold says the party went in on Monday and were due out Friday.
The last time anyone spoke to them was Wednesday around 6 p.m. via satellite phone. At that time the party was at 12,800 feet with plans to overnight.
Two climbing rangers on board a Hughes contract helicopter from Northwest Helicopters are conducting an air search and a US Army Reserve 214th Air Division Chinook out of Joint Base Lewis McChord is also providing air support.
Alpine Ascents' director of programs, Gordon Janow, said he wasn't ready to release information about the climbers. "Let's hope they're found and that it goes well," he said.
Details -- such as ages, gender or hometowns -- for the climbers were not immediately available.