Maria Janzen has been missing since Wednesday afternoon. The 76-year-old is considered to be at risk because of her age and because how of long she's been missing.
Janzen is described as having brown hair, brown eyes, 5 feet 5 inches tall and weighing about 100 pounds. The 76-year-old woman was reportedly wearing yellow foam sandals made by Crocs.
She was last seen in the area of Park Pacific Avenue in Pacifica and is known to walk the trails nearby.
Bay City News Service contributed to this story.