The 25-year-old woman was last seen leaving for a hike on Mt. Tamalpais on Dec. 3.
Her boyfriend, Robert Voigt, said the number of volunteers dwindled in the search during the last few weeks but they will now continue on a larger scale.
"You've got to understand, we just got through the holiday season," Voigt said. "These people are volunteering their time for enormous searches, especially this weekend and next weekend."
Ruiz' family describes her as 5 feet 5 inches tall, 120 pounds, with dark brown hair and brown eyes, a light brown complexion and a scar on her right abdomen.
Police are encouraging anyone with information on Ruiz's whereabouts to contact Detective Sgt. Dean Loutas at (415) 389-4100.
