Shasta Trinity National Forest Spokesman Mike Odle says Patricia Giamoni, who's from North Carolina, called 911 Saturday night to say she was in trouble. She and hiking companion Salvador Frias, a Millbrae resident, had applied for a day permit to hike the 14,162-foot mountain about 220 miles north of Sacramento.

"She quickly provided us with coordinates, and a description of the area she was in before her cell phone signal was lost," said Odle. "But the coordinates that she provided us placed her at about 12,000 feet on the south side of the mountain, while her verbal description placed her at the summit on the north side of the mountain. The two locations provide for a lot of area for this search to be taking place right now."

Odle adds that crews have conducted three rescues in the last 24 hours, and last week had to help someone off the mountain who was suffering from hypothermia.

Eight rescuers were dropped onto the mountain Monday by two blackhawk helicopters.

Searchers from Siskiyou County, the Forest Service, the California Highway Patrol and the California Air National Guard also scoured the area for the pair a day earlier.