Wildfires near the Chino Hills State Park increased 50 percent from 2012 to 2018, compared to the previous 97 years, according to a study released by Hills for Everyone, the group that founded the Chino Hills State Park.
Melanie Schlotterbeck, technical consultant for the non-profit organization, said the study covers the juncture of southern California: Orange, Riverside, San Bernardino and Los Angeles counties.
Ms. Schlotterbeck said the group decided to update its previous study, released seven years ago, after the catastrophic wildfires burned throughout California in 2017 and 2018.
According to the updated study, Carbon Canyon Road is a major hot spot with 20 percent of the fires starting there.
Traffic going from Orange County to San Bernardino County puts the Chino Hills State Park and Olinda Ranch community in Brea at risk, she said.
Other hot spots are the southern border of the Chino Hills State Park and the 91 Freeway in the Santa Ana corridor with more than 30 percent of fires starting there.
“It is clear that the 91 Freeway is a major contributor to our region’s devastating losses,” Ms. Schlotterbeck said. “Most recently, the Canyon 1 and Canyon 2 fires in 2017 wreaked havoc on the habitat lands and destroyed many homes.”
She said more than 151 wildfires have burned in the study area since 1914. Two of those were caused by lightning strikes, and the rest were caused by humans.
The document contains fire perimeters, points of origin, causes and weather conditions for fires that burned in, adjacent to, or near the Chino Hills State Park between 1914 and 2018.
Most of the new fires were small in size, extinguished quickly, and occurred on days that were normal for temperature, humidity and wind.
The three most prevalent fire months were July, September and October.
The top three most identifiable causes of wildland fires were arson, automobiles and fireworks, she said.
The data from the study is intended to inform fire, planning and transportation agencies where the problems are occurring to create fire buffers and avoid home-building, Ms. Schlotterbeck said.
“These precedent-setting fires should give pause to our decision makers when considering developments — but the opposite is true in Orange County where 340 houses were approved in the fire-prone hills above Yorba Linda, with just one way out for residents,” she said.
Recommendations include the development of a mechanism for fining violators to improve safety; the formation of Fire Watch programs where volunteers patrol streets on high wind days; the requirement by cities for state-of-the-art construction for fire prevention such as installing attic vents that close without human intervention; harden the edges of the 91 Freeway that abut natural lands with K-rails or similar structures; and enforce frequent maintenance for power lines owned or operated by Edison and other utility providers.
Ms. Schlotterbeck said there remains more than two miles of roadway along the 91 Freeway that touches open space that need to be hardened, and work is underway at the state level to bring attention to it.
The study, called “104 Years of Wildfire History near Chino Hills State Park” is available on the Hills for Everyone website with interactive digital map layers viewable in Google Earth by visiting hillsforeveryone.org.