NORTHERN CALIFORNIA – A wildland fire that began near Cloverdale on Sunday morning burned 1,500 acres by nightfall, with authorities implementing mandatory evacuations nearby.

The Sawmill fire began at approximately 10:43 a.m. Sunday in Sonoma County off Big Geysers Road and Geysers Resort Road, 10 miles east of Cloverdale, according to Cal Fire.

By Sunday night, the fire had reached the 1,500-acre mark, with containment at 10 percent, Cal Fire said.

The fire's huge smoke plume, which rose over the ridge and was visible from around Lake County, put many nervous Lake County residents on edge, with hundreds of concerned posts flooding the Internet and social media.

However, the fire still had not crossed into Lake County by Sunday night, according to Cal Fire.

Throughout the day Cal Fire had battled the fire hard from the air due to the steep, difficult-to-access terrain.

The agency called in additional ground crews from around the region, with Lake County's fire districts also sending help.

The Lake County Sheriff's Office also was reported to be assisting Sonoma County officials in the fire response.

On Sunday afternoon, a water tender responding to the incident rolled over on Geysers Road. Cal Fire did not identify the agency involved but said no injuries were reported.

Resources committed late Sunday included 473 firefighters, 36 fire engines, 13 fire crews, 10 dozers, eight airtankers, six helicopters and two water tenders. Cal Fire said still more units are on the way.

Cal Fire said vegetation – including grass and oak woodland – in the fire area is heavy and extremely dry due to the five years of drought conditions. Temperatures on Sunday were in the 70s with low relative humidity, and humidity expected to be in the low 20s through the night.

With structures threatened, the Sonoma County Sheriff's Office ordered a mandatory evacuation for Geysers Road on the Cloverdale side from Pine Mountain Road to Geysers Resort Road, with an evacuation warning for the area of Geysers Road on the Geyserville side from Geysers Resort Road to Anderson Ranch Road, Ridge Oaks Road, Monkey Rock Road and Pocket Ranch Road.

The agency asked residents in the surrounding Geysers area to stay vigilant and prepare for possible evacuation. Residents are urged prioritize their personal safety, and do not wait for an evacuation notification if they feel their safety is at risk.

At 5 p.m. Sunday the American Red Cross opened an evacuation center at the Good Shepherd Lutheran Church in Healdsburg, 1402 University St.

Cal Fire said the fire's cause is under investigation.

Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it. . Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.