Deputies camped out at trailheads in the San Bernardino mountains overnight in case three missing hikers descended down the hiking trails before a team of about 40 people set out Tuesday morning to resume the search.
The trio went missing over the weekend, and by Monday, weather conditions has worsened.
The hikers, all from Oceanside in San Diego County, set off to hike San Gorgonio Peak from Fish Creek Trail on Saturday morning. A fourth member, James Goins, turned back early because he felt out of breath and waited for them to return. But they never did.
Goins told NBC4 that the hikers were not prepared for the cold weather.
"I'm hopeful," said Niki Shankles-Burger, sister of one of the missing hikers. "My brother is very strong mentally and emotionally and spiritually. He's the MacGyver type that could live off the land if he had to."
San Bernardino sheriff's officials were searching the area on the ground and in the air. Snow levels in the area were expected to fall to 6,500 feet Monday night as a cold, wet storm moved across the region.
Temperatures early Tuesday were in the 30s.
The missing hikers, pictured below, were identified as David Yoder, 43, Ryan Shankles, 41, and Miguel de la Torre. The four hikers knew each other from the Oceanside church they attended together.
If the group does not run into deputies stationed at the trailheads, search teams will return to the rugged hiking trails at first light Tuesday.