'Unusual time of year for a wildfire': San Bruno Mountain blaze grows to 8 acres, 20% contained

A large plume of smoke could be seen around San Francisco Friday from a grass fire burning in the San Bruno Mountain State and County Park near the picnic. A large plume of smoke could be seen around San Francisco Friday from a grass fire burning in the San Bruno Mountain State and County Park near the picnic. Photo: San Francisco Fire Department Photo: San Francisco Fire Department Image 1 of / 7 Caption Close 'Unusual time of year for a wildfire': San Bruno Mountain blaze grows to 8 acres, 20% contained 1 / 7 Back to Gallery

A grass fire that started at 10:30 a.m. Friday on San Bruno Mountain had grown to 8 acres by 2:30 p.m. and was 20% contained, officials said.

The North County Fire Authority said a helicopter was being released to help stop the three-alarm blaze that pumped out a massive cloud of smoke visible throughout San Mateo County and the southern end of San Francisco.

The blaze started in San Bruno Mountain State and County Park near the Battle Trail and picnic area.

Sixty fire fighters were on the scene and no evacuations are in place. There are no injuries.

The San Francisco Fire Department tweeted a video showing the blaze pumping out smoke.

The park is located in northern San Mateo County. People should avoid the area, officials said.

The Bay Area hasn't seen any rain in February and vegetation is becoming increasingly dry for this time of year.

"This is an unusual time of year for a wildfire," Cal Fire shared on Twitter. "This is a stark reminder that we need to be prepared!"

Amy Graff is a digital editor with SFGATE. Email her news tips and photos at agraff@sfgate.com.