June 2020

Nonprofit study examines fire frequency in local mountains

A fire study produced by Friends of Harbors, Beaches and Parks reveals that, since 1914, the Santa Ana Mountains have experienced 218 wildfires, with only one known to be caused by lightning, 36 resulting from human activity, four prescribed burns and 171 of unknown origin.

The study used available data to document fire perimeters, points of origin, causes and weather conditions.  A goal was to identify “hot spots” and provide recommendations to alleviate hazards.


While fires of “unknown cause” represent the highest number and the most acreage burned, arson is the leading cause.  Over the 100-plus years the study covered, 56,329 acres burned in 11 separate deliberately-set fires. Campfires, equipment, debris, vehicles and firearms accounted for 101,074 acres burned.

There were two fires caused by power lines, both prior to 2014.  Most fires burned in the summer, but the study found there are are no fire-free months.


There are four areas in the Santa Ana Mountains with a propensity to burn: along the 241 Toll Road, Santiago Canyon Road, Ortega Highway and within the San Mateo Wilderness.  Of the two areas nearest to the East Orange foothill area, most fire ignitions occurred along Santiago Canyon Road.

Among the preventive measures recommended by the study are: continued fire watch programs, brush clearance, invasive plant removal, hardened edges along roadways, de-energizing power lines during Santa Ana winds, and not building houses in very high, or high, wildfire hazard severity zones.

The full report is available at FHBP.org.