California has dry, windy, and often hot weather conditions from spring through late autumn that can produce moderate to severe wildfires.
In total, more than 2.7 million people live in "very high fire hazard severity zones", which also include areas at lesser risk.
[13] On lands under CAL FIRE's jurisdictional protection (i.e. not federal or local responsibility areas), the majority of wildfire ignitions since 1980 have been caused by humans.
Orange and San Bernardino counties share a border that runs north to south through the Chino Hills State Park, with the park's landscape ranging from large green coastal sage scrub, grassland, and woodland, to areas of brown sparsely dense vegetation made drier by droughts or hot summers.
The valley's grass and barren land can become easily susceptible to dry spells and drought, therefore making it a prime spot for brush fires and conflagrations, many of which have occurred since 1914.