In some parts of California, fires can recur in areas with histories of fires. Examples of this are in Oakland , where fires of various size and ignition occurred in 1923 , 1931, 1933 , 1937, 1946, 1955, 1960, 1961, 1968, 1970 , 1980 , 1990 , 1991 , 1995, 2002, and 2008.   Other examples being Orange County , Riverside County , San Bernardino County , and Los Angeles County . In the case of Orange and San Bernardino, these two counties share a county 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 conflagration , many of which have occurred since 1914. Hills and canyons have seen brush or wildfires in 1914, the 1920s, 1930s, 1940s, 1950s, 1960s, 1970s, 1980s, 1990s, 2000s, and into today.