Note: Total number of large wildfires and acres burned to-date calculated using data collected by Watch Duty. Watch Duty is a 501(c)(3) non-profit responsible for tracking and alerting all wildfire and firefighting efforts in real-time throughout the American West. Fatalities and structures damaged or destroyed to-date collected from incident data hosted on Cal Fire's website.
Would you like to know more?
When is fire season in California?
- As the climate crisis intensifies, California faces the risk of wildfires all year now, particularly in years of extreme drought conditions that leave the state's foliage a tinderbox.
- Most fires happen between the months of April and October, as weather becomes warmer and drier. In Southern California in particular, the hot and dry Santa Ana winds increase wildfire risk in October and November.
- Some of the worst wildfires in California history occurred outside that window. The Camp Fire in 2018, which killed 85 and destroyed the town of Paradise outside Redding in Northern California, was a November fire.
How large have wildfires been over time?
- Megadroughts and rising temperatures aggravated by climate change have increased the frequency and intensity of California wildfires in recent years.
- As of 2022, half of the state's 20 largest fires had occurred over the previous five years. Of those, seven occurred in 2020 and 2021. All but two of the state's largest fires occurred in the 21st century.
|August Complex||1,032,648||August 2020||Mendocino, Humboldt, Trinity, Tehama, Glenn, Lake, Colusa|
|Dixie||963,309||July 2021||Butte, Plumas, Lassen, Shasta, Tehama|
|Mendocino Complex||459,123||July 2018||Colusa, Lake, Mendocino, Glenn|
|SCU Lightning Complex||396,625||August 2020||Stanislaus, Santa Clara, Alameda, Contra Costa, San Joaquin|
|Creek||379,895||September 2020||Fresno, Madera|
|LNU Lightning Complex||363,220||August 2020||Napa, Solano, Sonoma, Yolo, Lake, Colusa|
|North Complex||318,935||August 2020||Butte, Plumas, Yuba|
|Thomas||281,893||December 2017||Ventura, Santa Barbara|
|Cedar||273,246||October 2003||San Diego|
- Three major blazes ignited by lightning strikes in August 2020 made that year one of the worst on record for total acres burned. At least 4.3 million acres burned, blanketing large parts of California with toxic smoke for weeks.
- Cal Fire classifies any wildfire that burns 300 or more acres as a "large fire.”
- Since 2008, the destructiveness of large wildfires has been rising, particularly for acres burned per fire.
What causes wildfires?
- As you would expect, wildfires ignite in many ways. Since 2008, large fires caused by lightning strikes have destroyed close to 7 million acres of land, followed by 2.7 million acres destroyed due to human causes, not counting the nearly 2 million acres due to malfunctioning power company infrastructure.
- Lightning strikes can cause widespread damage in the most remote areas of the state. Mixed with super-dry conditions, you get something like the fire siege of 2020 – the state's most destructive fire year on record in terms of acres burned – when several massive wildfires ignited throughout the state around the same time, destroying millions of acres of land and blanketing the state with toxic smoke for weeks.
- People can start wildfires intentionally, through arson, or unintentionally, through an equipment mishap or an untended campfire. The state's third largest wildfire – the 2018 Mendocino Complex fire – was caused by sparks from a hammer and grew to consume 460,000 acres.
- Finally, power companies, such as PG&E, can cause destructive wildfires through delayed maintenance of power transmission and distribution equipment, or downed power lines due to bad weather. One example was the 2018 Camp Fire – the state's most deadly and destructive on record – in which PG&E was found liable for its cause.
- Investigators are unable to determine the cause of every wildfire. Since 2008, large wildfires that burned 3.7 million acres of land were either still under investigation at the time of Cal Fire's annual fire report, or a cause was never determined.
California wildfire history as fire perimeters since 1900
Source: National Interagency Fire Center
Cost of Wildfires
How many people have died due to wildfires?
- Cal Fire tracks how many firefighters and civilians have lost their lives in wildfires. Since 1992, at least 268 people have died in a wildfire, and since 2008, 193 civilians and 32 firefighters lost their lives.
- Half of California's 20 deadliest fires occurred in the 21st century. The deadliest fire in California history was the Camp Fire in 2018, which destroyed the town of Paradise and killed 85 people.
|Camp Fire (Paradise)||85||November 2018||Butte|
|Griffith Park||29||October 1933||Los Angeles|
|Tunnel (Oakland Hills)||25||October 1991||Alameda|
|Tubbs||22||October 2017||Napa, Sonoma|
|North Complex||15||August 2020||Butte, Plumas, Yuba|
|Cedar||15||October 2003||San Diego|
|Loop||12||November 1966||Los Angeles|
|Hauser Creek||11||October 1943||San Diego|
|Inaja||11||November 1956||San Diego|
- This does not include people who may have died later due to exposure to smoke, which contains toxic gasses and fine particles.
What's the mental toll on firefighters?
- Firefighters and high-ranking fire officials say PTSD and suicidal thoughts are an epidemic at Cal Fire. The state agency doesn't compile data on suicides or PTSD; it only tracks the number of times that firefighters and their families reach out for assistance over issues such as grief, substance abuse and suicidal thoughts.
- Firefighters are more likely to die of suicide than in the line of duty. Read more about the mental health impacts on firefighters at the link below.
What's the financial cost?
- Cal Fire reports the "dollar damage" of wildfires in their annual Redbook report.
- Dollar damage is defined as "estimates of the total property and contents dollar loss in terms of replacement in like kind and quantity.” It includes “property and contents damaged by fire, smoke, water, and overhaul."
- Dollar damage does not include fire suppression or indirect costs, such as lost economic activity.
How many structures have been impacted by wildfires?
- When wildfires sweep across the landscape, they destroy houses, buildings and infrastructure, such as water pumps and power lines.
- Cal Fire tracks how many structures were damaged or destroyed in fires. Strucutres include homes, commercial properties and outbuildings, such as barns, garages and sheds.
|Camp Fire (Paradise)||18,804||November 2018||Butte|
|Tubbs||5,636||October 2017||Napa, Sonoma|
|Cedar||3,021||October 2003||San Diego|
|North Complex||2,352||August 2020||Butte, Plumas, Yuba|
|Valley||1,958||September 2015||Lake, Napa, Sonoma|
|Witch||1,650||October 2007||San Diego|
|Carr||1,614||July 2018||Shasta, Trinity|
|Glass||1,528||September 2020||Napa, Sonoma|
|LNU Lightning Complex||1,491||August 2020||Napa, Sonoma, Yolo, Stanislaus, Lake|
- Nine of the 20 most destructive fires occurred in the last five years, and all but two occurred in the 21st century. The most destructive fire on record was also the deadliest: the Camp Fire in 2018, which destroyed the city of Paradise.
How much has been spent on fire suppression?
- Cal Fire routinely spends more money than allocated in its budget to suppress wildfires.
- Fire suppression costs surpassed the billion dollar mark for the first time in 2020.
Interested in joining the conversation about how to protect your communities from wildfires? Here are options:
- Engineering: John Osborn D'Agostino and Jeremia Kimelman
- Data: John Osborn D'Agostino and Jeremia Kimelman
- Design: John Osborn D'Agostino
- Editors: Vicki Haddock, Marla Cone, and John Osborn D'Agostino
- California is a big state with big challenges. Sign up for CalMatters’ newsletters for reporting that explains potential solutions.