UPDATE 3 p.m.: Firefighters quickly extinguished a grass fire that started about 1:50 p.m. in the 6000 block of Rocky Canyon Road.
The fire was put out at 2:24 p.m. The one threatened structure, a residence, was not damaged.
Original story: Fire personnel are responding to a grass fire in the 6000 block of Rocky Canyon Road, east of Atascadero, which is believed to have been started by a downed power line, according to Cal Fire.
Cal Fire received the report at 1:52 p.m. So far, the blaze is about 2 acres, and is threatening one structure. Fire personnel from the Atascadero Fire Department, Atascadero State Hospital and Cal Fire are responding, about 70 people total.