Glacier National Park in Montana, where two area hikers are presumed lost, spans over 1,000,000 acres.
Update: The two Virginia area hikers reported missing in Glacier National Park last Friday have been found, the Associated Press reports.
Neal Peckens of Herndon and Jason Hiser, of Richmond, both 32, were reported missing Friday, when they failed to make their return flights after a camping trip in Glacier National Park.
Park officials say the men had a camping permit and started hiking on the east side of the park. Peckens' aunt told The Herald Mail newspaper in Hagerstown that her nephew is an experienced hiker.
But winter is moving into the park at this time of year, with up to 18 inches of snow in some areas and high winds causing drifts of up to 5 feet.
Low clouds are preventing searches by air, so some of the crews are on foot, some on horseback and others are equipped with search dogs.
Both men are veterinarians and originally from western Maryland.