Updated at 11:53 a.m. ET
RANCHO SANTA MARGARITA, Calif. Southern California authorities are resuming the search for a young man and woman who vanished during a weekend hike in Cleveland National Forest.
Orange County sheriff's Lt. Erin Giudice says dozens of searchers, a cave rescue team, horses and bloodhounds will scour the area Tuesday for 19-year-old Nicholas Cendoya and 18-year-old Kyndall Jack.
She says helicopters will be used if morning fog clears. An overnight search proved fruitless.
Air and ground search crews searched throughout Monday, but there was no sign of the hikers, authorities told CBS Los Angeles station KCBS-TV. The search was centered on an area of heavy brush.
Sheriff's spokeswoman Gail Krause says Cendoya and Jack, both of Costa Mesa, called authorities Sunday night saying they were lost about a mile from their car in Holy Jim Canyon, but their cell phone lost power soon after.
Authorities say they found a vehicle belonging to one of the hikers.
An Orange County Sheriff's lieutenant told KNX she was optimistic the hikers would be found in relatively safe condition due to their young age and favorable weather.