The fire was reported at 4:15 p.m. in a grassy area behind the Orchard Supply Hardware store at Woodside and Middlefield roads, Redwood City fire Deputy Chief Stan Maupin said.
The fire spread to some trees and was visible to passing motorists, the deputy chief said.
Crews contained the blaze by 4:30 p.m., and were leaving the scene as of 5:15 p.m., Maupin said.
No injuries were reported, but the fire affected power in the immediate vicinity.
Authorities were advising motorists to avoid the intersection because traffic signals were down. The Redwood City Police Department and the San Mateo County Sheriff's Office were monitoring the area and directing traffic.
Caltrain service was affected by the fire and subsequent outage, and trains were traveling through the Redwood City area at decreased speeds, Maupin said.
Crews from the Menlo Park and Woodside fire protection districts assisted in tackling the grass fire, Maupin said.