LIVERMORE — Crews by Friday morning had mostly contained a 260-acre wildfire that spread fast Thursday near Livermore, Tracy and the junction of Interstate 580 and Interstate 205.

The blaze had burned 262 acres and was 85% contained by 7:15 a.m. Friday, according to Cal Fire. The fire did not damage any structures.

The blaze seemed to signal the arrival of wildfire season in the Bay Area, even as weather conditions were far from extreme.

Fire crews contained 75% of the fire by 7:30 p.m. Thursday.

“We’re in our mop-up phase right now,” Cal Fire spokesperson Chelsea Burkett said Thursday.

Ground crews cooled hot spots in the burn area and remained through the night to monitor the scene, Burkett said.

The fire sparked at about 3 p.m. Thursday near the intersection of Patterson Pass Road and Midway Road, according to the agency.

Air and ground resources quickly battled the brush fire, which had jumped I-580 and snarled traffic in the region. Firefighters held the fire’s progress at a local aqueduct.

Burkett said the fire had spread quickly in fields of dry grass, fed by winds.

“The wildland season has begun,” the Alameda County Fire Department’s union posted on social media.

Staff writer Rick Hurd contributed to this report.