A fast-moving grass fire driven by strong afternoon winds scorched 139 acres off Patterson Pass Road southwest of Tracy on Wednesday.
The first report of a grass fire on three to five acres came just before 5 p.m. It burned through dry grass along the hillsides as commuters returned from the west along the two-lane road.
Firefighters from Tracy, Alameda County and Cal Fire were sent to the scene. Cal Fire sent air tankers that dropped lines of fire retardant to stop the progress of the flames. A helicopter was also dispatched to help by dropping water on the fire.
By 5:30 p.m., the fire had reached the eastbound lanes of Interstate 580. Freeway traffic was stopped in both directions as heavy smoke obscured the roadway.
By roughly 6:20 p.m., fire crews had stopped the forward progress of the fire, which had consumed about 100 acres, and they called the fire fully contained nearly 15 minutes later.
Traffic on the freeway was released at about 6:14 p.m., with on-ramps opening shortly after that.
Cal Fire estimated that the fire, which it named the Patterson Fire, burned a total of 139 acres. No one was hurt and no structures were damaged.