Firefighters quickly extinguished a small grass fire burning along U.S. Highway 101 that snarled traffic heading out of San Francisco this afternoon, according to North County Fire officials and the California Highway Patrol.

The fire was reported shortly after 1 p.m. along southbound Highway 101 near the Alana Way onramp, in the area of Candlestick Park.

North County Fire Safety Inspector Joe Perez said crews were able to extinguish the “extremely small” fire in less than 10 minutes after arriving on scene.

According to the CHP, two lanes of the roadway remained blocked as of 1:40 p.m., but all lanes reopened a short time before 3 p.m.

Initial reports indicated that the fire may have been sparked by flares, and one motorist reported to the CHP that the heat from the flames could be felt in the slow lane.

Perez said a cause for the fire has not been determined. However, he reminded motorists and passengers not to discard cigarettes along the roadway.

Please make sure your comment adheres to our comment policy. If it doesn't, it may be deleted. Repeat violations may cause us to revoke your commenting privileges. No one wants that!