Crews searching for two mountain climbers missing on one of Alaska's most difficult peaks have found a torn backpack, radio and sleeping bag, and fear the women have now been without food and fuel for over week.

Sue Nott and Karen McNeill, both experienced climbers, started up Mount Foraker on May 14 and planned to complete the route in 10 to 14 days.

The search for them began June 1 after an air taxi operator flew the ascent route and didn't see them on the mountain.

"Given the harsh conditions up there, it makes the possibility that they have survived less and less with each passing day," said Kris Fister, spokeswoman for Denali National Park and Preserve.

Cloudy weather Thursday grounded the high altitude helicopter being used in the search, and Fister said the base camp where the women started was "socked in."

A ripped backpack believed to be Nott's, a radio and sleeping bag were spotted Friday in an avalanche debris field. Nott, 36, of Vail, Colo., and McNeill, 37, of Canmore, Alberta, Canada, had not been communicating on their radio. A helicopter crew on Sunday found a yellow bag, black fleece hat and pink nylon jacket in the same area.

Searchers on Monday spotted footprints at 16,400 feet.

Fister said searchers theorize that the climbers may have burrowed into a sheltered spot, such as a crevasse, to reduce exposure to the wind and subzero temperatures.

Mount Foraker is 12 miles southwest of Mount McKinley, North America's highest peak. The 17,400-foot mountain is considered a difficult and technical climb, attracting far fewer people than McKinley.