Time was running short Tuesday in the search for two missing climbers on Mount Hood, as heavy snow grounded a search helicopter and prevented ground crews from leaving camp.

The storm that hit the mountain late Monday was expected to dump up to two feet of new snow on the slopes where Anthony Vietti, 24, of Longview, Wash., and Katie Nolan, 29, of Portland have been missing since Friday.

SLIDESHOW: Missing Climbers on Mount Hood

The bad weather was expected to remain until Thursday, raising the risk of an avalanche that could further complicate the rescue effort.

"It doesn't look good," Jim Strovink, spokesman for the search and rescue operation, said about the forecast. "This could hang on for a couple of days."

Rescuers still consider their work a search and rescue mission rather than a recovery operation.

Steve Rollins, a search leader, said rescuers were still hopeful the two climbers had dug a snow cave to shelter them from the storm.

"We are still being very optimistic," Rollins said. "I've been in plenty of snow caves in complete blizzards. You don't know what the weather is like outside."

Strovink said an expert in hypothermia and mountain survival planned to speak to the families gathered at Timberline Lodge.

Searchers found the body of one climber, Luke Gullberg, 26, of Des Moines, Wash., on Saturday at an elevation of about 9,000 feet. An autopsy showed he suffered minor injuries in a fall and died of hypothermia as overnight lows on the mountain dipped into the teens.

Intermittent snow and subfreezing temperatures have hampered the search since it began. On Monday, however, searchers got an unexpected break in the weather and dispatched a helicopter to search for signs of Vietti and Nolan.

"I couldn't have hoped for better weather conditions," said Monty Smith, a mountain climber in the helicopter that was finally able to survey the heights of the 11,249-foot peak.

However, there was "no sign at all" of the missing climbers, he said.

Rollins said the climbers had ice axes that could be used to hack out a snow cave.

"It's more like digging with a spoon than a shovel, but if your life is in danger, you can do wonderful things," Rollins said.

Some equipment was found with Gullberg's body, but it hasn't helped rescuers determine what went wrong on a climb that was supposed to reach the summit and return in a single day.

Authorities said the mountaineers who found Gullberg's body didn't find his pack, which led family members to think he had left it behind with Nolan and Vietti and headed down the mountain for help.

Experts with Portland Mountain Rescue, though, said the evidence didn't point strongly to any particular scenario.

Also among the items found with Gullberg were a water bottle and glove believed to have belonged to Nolan, said Deputy Scott Meyers, commander of the search and rescue operation.

Photos from Gullberg's camera also showed the group had helmets, ropes and other standard mountaineering gear. Officials previously said the climbers did not have a shovel.

Gullberg's body was found on a flat area near the base of a headwall rising at a 50-degree angle to an elevation of 10,500 feet, Rollins said.

Other photos showed the trio had been roped together at some point, but rescuers found no rope with Gullberg's body.

"That's a big part of the mystery. Where's the rope? Why wasn't the group together?" Rollins said.

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