Aircrews have been dropping retardant and water.
Fire officials say a large plume of smoke can be seen from Santa Rosa.
*Vegetation Fire - Sharp Road - Northeast of Santa Rosa (Outside City Limits)* Santa Rosa Fire is responding to a report of a fire on Sharp Rd off Petrified Forest Rd in Sonoma County Fire Dist. The fire is visible from Santa Rosa and can be viewed at https://t.co/xkO0cVzfsQ pic.twitter.com/M5b6LMbXEL— Santa Rosa Fire Department (@SantaRosaFire) August 20, 2019
The fire is burning near Calistoga. An alert has been sent out warning residents that smoke is drifting into the city.
No homes are threatened right now, and Cal Fire says the fire is spreading slowly.
At least three acres have burned.
Stay with ABC7 News for more on this developing story.