GILROY, Calif. -

Firefighters were still working late Monday night, trying to figure out how a brush fire started on private property along Highway 152 in Pacheco Pass as hot weather and high winds made the fight difficult.

Just over 20 acres burned on the property and broke out just before 2:30 p.m.
 
"If it had gone up the hill, we'd have been here a couple of days," said Fire Chief Mike Jarske with CalFire Santa Clara.

Firefighters called it a "dirty burn" as trees and debris were in the path of the flames, but the landscape helped responders.

"It got into the creek and that slowed it down. It was one of those natural barriers that we often use to help us with containment lines and the creek helped slow it down a bit," said Jarske.

Jarske said CalFire is paying extra close attention to some of the common causes of brush fires ahead of the Fourth of July weekend like sparks from cars, fireworks, or cigarettes.

The area in Hollister Monday afternoon reached 100 degrees and firefighters said that contributed to the very hot and fast moving fire, one of several crews were working to put out.

A second fire was reported near the city of Gilroy on Highway 152 at Holsclaw Road, but crews left Pacheco Pass to check it out and didn't find anything.