However, from a historical perspective, it has been estimated that prior to 1850, about 4.5 million acres (17,000 km²) burned yearly, in fires that lasted for months, with wildfire activity peaking roughly every 30 years, when up to 11.8 million acres (47,753 km³) of land burned. At times, these wildfires are fanned or made worse by strong, dry winds, known as Diablo winds when they occur in the northern part of the state and Santa Ana winds when they occur in the south. United States taxpayers pay about US$3 billion a year to fight wildfires, and big fires can lead to billions of dollars in property losses. Wildfires in California are growing more dangerous because of the accumulation of wood fuel in forests, higher population and greater electricity transmission and distribution lines. During the 2020 wildfire season alone, over 8,100 fires contributed to the burning of nearly 4.5 million acres of land. California land area totals 99,813,760 or roughly 100 million acres, so since 2000, the area that burned annually has ranged between 90,000 acres, or 0.09%, and 1,590,000 acres, or 1.59% of the total land of California. Pre-1800, when the area was much more forested and the ecology much more resilient, 4.4 million acres (1.8 million hectares) of forest and shrubland burned annually. California has dry, windy, and often hot weather conditions from spring through late autumn that can produce moderate to severe wildfires. This is a partial and incomplete list of California wildfires. Santa Ana winds in California expand fires and spread smoke over hundreds of miles, as in this October 2007 satellite image The Rim Fire consumed more than 250,000 acres (100,000 ha) of forest near Yosemite National Park, in 2013 For the current fires in California, see 2023 California wildfires.

California fire risk map 2021