"It would expose our rangers to pretty extreme conditions," Bauer said. "And, in all honesty, we may never be able to get on the ground there."
Aircraft will survey the area periodically in the coming weeks and months, Wold said, but the possibility of recovering the six is uncertain.
The missing group includes four clients of Seattle-based Alpine Ascents International and two guides. They were due to return from the mountain on Friday. When they did not return, the climbing company notified park officials, Bauer said.
Officials have yet to finish family notifications, so the names of the climbers are unlikely to be released until Sunday.
"The climbing community is a small one and a close one and a loss of this magnitude touches many," Superintendent Randy King said in the statement.
Mount Rainier, southeast of Seattle, stands at 14,410 feet and attracts thousands of climbers trying to reach its summit every year.
The search for the missing climbers focused on the northwest shoulder of the mountain at the Liberty Ridge area, near where they were last heard from, Bauer said. Saturday's search included a team of three climbing rangers on the ground and flyovers with a Hughes helicopter. An Army Chinook helicopter then joined the search from Joint Base Lewis-McChord.
The group was scheduled to reach the summit of Mount Rainier on Thursday, with a day to climb down.
Snow flurries and hail hit the mountain Wednesday, Bauer said, but the weather has been clear since then.
Bauer said ground crews on Saturday checked "every possible area" where someone could have sought refuge in the storm.
Alpine Ascents' director of programs, Gordon Janow, said he wasn't ready to release information about the climbers. Details — such as ages, gender or hometowns — for the climbers were not immediately available, Bauer said.
In a statement from the park, the guides were described as skilled.
In a blog post on the Alpine Ascents website Thursday, the post said the team had turned around at 13,000 feet during their attempt to reach the summit because of weather conditions. The blog post said all team members were well.
DuBois reported from Portland, Oregon.