Katherine Truitt, 37, was last seen by her roommate Thursday after leaving her home in Alameda to go on a hike.
The rescue effort is being led by the Marin County Sheriff's Department.
"We're told she is very familiar with this area; she's been hiking here for 20 years or more," National Park Service spokesperson John Dell'Osso said.
Truitt never called her parents like she normally does after a hike. Park rangers discovered her Ford Ranger parked at McClures Beach on Friday.
"The vehicle and items inside are intact, nothing seems disturbed; the only question is, 'Where is she,'" Dell'Osso said.
Park rangers say they do not suspect foul play. Instead, they suspect the allure of the cliffs and their natural beauty.
"There are precipitous cliffs out here and people come out only to be trapped," Dell'Osso said.
Rangers say hikers have been cornered in cove beaches when the tide comes back in. Helicopters have been grounded because of the low cloud ceiling and searchers hope they will spot her when the weather lets up.
Truitt is 6 feet tall and weighs 145 pounds. She was last seen wearing blue jeans, a light-colored sweatshirt and black shoes. She was also carrying a green or black backpack.
