The woman was described as an experienced hiker who went on day trips.
Authorities fear she may have fallen and injured herself.
The San Bernardino Sheriff's Dept. contacted the Forest Service. The woman's vehicle was located near Mt. Baldy and Falls roads.
Hikers in the area reported hearing someone shouting from a canyon at about 6 p.m. Sunday, but could not determine from exactly where.
A search-and-rescue team went looking for the woman and used a helicopter to scope the area.
Rain, snow and fog at the 8,000-foot level presented problems for the rescue team. Visibility was limited to less than 15 feet.
Four search sheriff's teams were expected to continue searching through the night.
