A small south Santa Rosa grass fire damaged a few PG&E power poles, burned some of the utility’s underground equipment and snarled traffic on Petaluma Hill Road Monday afternoon.

Around 3 p.m., Santa Rosa firefighters responded to the southeast corner of Petaluma Hill and Kawana Springs roads, where some grass and four power poles were on fire in an otherwise vacant field, according to Battalion Chief Mark Basque.

Firefighters quickly got the blaze under control, but it caused “quite a traffic jam,” Basque said. Northbound traffic was briefly shut down and Santa Rosa police issued a notice at 5:10 p.m. urging motorists to avoid the area.

The fire burned an approximately 50- by 50-foot area and at least two of the poles sustained significant damage, according to Basque. PG&E must restore an underground cable that was damaged by the fire and is still determining whether any of the poles need to be replaced, said spokeswoman Deanna Contreras.

Some 3,300 customers lost power for about 20 minutes while the fire was being fought, Contreras said.

No structures were threatened and no evacuations were needed.

The cause of the fire is still under investigation. Fire officials aren’t sure if the blaze began as a grass fire that spread to the poles or if an issue with the PG&E equipment caused the grass fire, Basque said.

You can reach Staff Writer J.D. Morris at 707-521-5337 or jd.morris@pressdemocrat.com. On Twitter @thejdmorris.

To read all of the Press Democrat's fire coverage, click here.

Remembering the October fires
On Oct. 9, fire-affected schools will acknowledge the anniversary in different ways.

Anova Center for Education
Students will take a field trip to Safari West, a wildlife sanctuary.

Schaefer Charter School
A motivational speaker will talk to students about making good life choices.

Mark West Union School District
Students from schools throughout the district will deliver trees to neighborhood parks in Mark West and Larkfield Estates.

Hidden Valley Elementary School
The annual pasta dinner will be held that evening for families to attend. Additionally, students are gathering toiletries, small toys and gift cards to put in 150 shoeboxes to send to two Shasta County schools affected by the Carr fire.

Cardinal Newman High School
Students will gather in the gym that morning for prayerful remembrance, a video presentation of students fire experiences and speeches administrators.