Two climbers missing on Mount Hood for the past five days are likely dead and a search will not resume anytime soon because of severe avalanche danger, officials said Tuesday.

Dr. Terri Schmidt, an expert on hypothermia and mountain survival, said there was less than a 1 percent chance that Anthony Vietti and Katie Nolan had survived after going missing on Friday.

The body of a third member of their party, Luke Gullberg, 26, of Des Moines, Wash., was found on the mountain Saturday. Officials have said he died of hypothermia after surviving a long fall.

SLIDESHOW: Missing Climbers on Mount Hood

Schmidt spoke at a news conference called by rescue officials. She talked with relatives of the missing climbers earlier in the day about the chances of survival in the extreme conditions on Mount Hood. Schmidt said she gave them the same statistic and they said they didn't want rescuers to be put at risk of encountering an avalanche.

Steven Rollins, a rescue leader, said search teams would not be going back up the mountain anytime soon because of avalanche dangers made worse by an ongoing storm that has created whiteout conditions.

Rollins, with Portland Mountain Rescue, said it would take four to five days of good weather to ease the avalanche risk, but such stretches were rare in the winter on Mount Hood.

"We can't get people off the ground. ... Our hands are really tied," Rollins said. "If there is anything we could do, we would do it."

Even if the rescuers knew where the two climbers were, search teams would not be able to get to them because of the danger, Rollins said.

The Mount Hood ordeal began last Friday when the trio was reported missing. They had started up earlier in the day on what was expected to be a one-day outing.

Ground teams and aircraft have been hindered in the search by snow, poor visibility and subfreezing temperatures.

Vietti, 24, is from Longview, Wash., and Nolan, 29, is from Portland.

Nate Thompson, a rescue coordinator, said it was not known if Vietti and Nolan had the equipment to survive for an extended period — such as a camp stove to melt snow for drinking water.

Officials have been piecing together a theory about what happened to the climbers from photos found in the camera next to Gullberg's body and from gear discovered around him. Rescuers think the tragedy began on the Reid Headwall, a snow- and ice-covered slope that starts at the 9,000-foot level and rises to 10,500 feet, some 740 feet beneath Mount Hood's summit.

Thompson said it appears "there was some sort of accident" as the trio climbed the headwall, and Gullberg was heading back down for help when he fell.

Thompson surmises that the first accident may have involved Nolan.

Gullberg died at the base of the headwall. Among the items near him was one of Nolan's gloves. Rescuers think Gullberg may given Nolan both of his gloves, and took the one glove she had left as protection for himself.

Rescuers don't know what happened to Vietti and Nolan after Gullberg fell, but they speculate the two were still high on the headwall. Conditions have been too severe for searchers to get that high, although a military helicopter inspected the area Monday and spotted nothing.

Click here for the latest news from KPTV Fox.