Up on Mount Laguna, on a late August day on which the thermometer had hit 92, Talbot Hayes scooped a dead piece of pine tree off the ground and gently gave it a twist.

The wood turned into crunchy splinters that fell to his feet, creating a puff of orange dust that briefly hung in the still air of the Cleveland National Forest.

“We are primed to burn,” said Hayes, who manages a fire fighting division for the U.S. Forest Service, which oversees the land. “Things could get bad.”

Runaway wildfires are always a possibility in the fall, when Southern California is raked by stiff Santa Ana winds that blow across the region’s ubiquitous chaparral, the most flammable mix of brush land vegetation in the country.

But this fire season may