Winds reaching 40 mph Friday created white-out conditions that hampered a search for two overdue parties at Mount Rainier National Park, and the forecast doesn't call for much improvement during the weekend.

The severe conditions forced searchers to withdraw from the field, though they remained on standby to return to the search upon the first sign of improved conditions.

A helicopter and pilots from Joint Base Lewis McChord were not cleared to fly until late Friday morning due to an ice storm that hit western Washington. Once cleared of the icy conditions, the limited visibility on the mountain was not favorable for a flight. They remain on standby to assist in the search.

There are two teams of overdue parties currently on the mountain. A party of two, Mike Vucich, 37, of San Diego, and Michelle Trojanowski, 30, of Atlanta, Georgia, were planning to winter camp on the Muir Snowfield over the weekend, according to park officials, who said the couple was due out last Sunday.

A second party of two climbers, Sork (Erik) Yang, 52, of Springfield, Oregon, and Jin Seol Hee, from Korea, on a summit attempt via the Disappointment Cleaver route, was due back Monday, officials added.

Due to weather conditions it is expected that they were waiting out the weather before attempting to descend to Paradise. Visitors to the upper mountain are advised by park officials to stop moving, dig in and wait for better weather during severe weather and white out conditions.

Park staff and searchers remain optimistic that both parties will be found alive. They are equipped for winter camping and carried extra food.

The weather forecast calls for snow, temperatures in the teens and 20s, and high winds through at least Monday. For more information on weather conditions visit the park weather webpage http://www.nps.gov/mora/planyourvisit/weather.htm