Facts + Statistics: Wildfires

Wildland fires

As many as 90 percent of wildland fires in the United States are caused by people, according to the U.S. Department of Interior. Some human-caused fires result from campfires left unattended, the burning of debris, downed power lines, negligently discarded cigarettes and intentional acts of arson. The remaining 10 percent are started by lightning or lava.

According to Verisk’s 2019 Wildfire Risk Analysis 4.5 million U.S. homes were identified at high or extreme risk of wildfire. According to latest Verisk estimates, in California, there were more than 2 million properties at high to extreme wildfire risk in 2021, the largest number of properties of any U.S. state. (See chart: States At High To Extreme Wildfire Risk, 2021, below.)

Wildfires by year

2021 Wildfires

This year’s wildfire season was predicted to be another severe one. According to the U.S. Drought Monitor by August 31, about 90 percent of land in the Western states was experiencing moderate to severe drought. Compounded by June’s heat wave, the threat of wildfires appeared a month ahead of schedule.

From January 1 to November 26, 2021 there were 52,729 wildfires, compared with 52,113 in the same period in 2020, according to the National Interagency Fire Center. About 6.6 million acres were burned through November 26, compared with 8.9 million during the same period in 2020. On November 26, 2021, three states reported four large fires including Alabama, which had two fires and California and Montana where each had one fire burning. Record rainfall that occurred at the end of October point to the end of the fire season for northern California, but also brought debris flows to the area. However, the situation is different in southern California, which did not have as much rain. Further, that region’s prime fire months often come in November and December.

Earlier fires included the Bootleg Fire In Oregon, ignited on July 6, that burned 413,7617 acres before being contained. In California, the Dixie fire is the second largest fire on record in the state, according to Calfire, and is second only to the August Complex fire of August 2020 which burned over a million acres. The Dixie fire burned 963,309 acres and destroyed 1,329 structures in five counties and damaged 95 structures. The Monument Fire burned about 223,100 acres. The Caldor fire burned about 222,000 acres, destroyed 1,003 structures and damaged 81. The Beckwourth complex fire which includes the Sugar Fire and Dotta Fire in Plumas County burned 105,670 acres. About 8,200 fires in California have burned about 2.5 million acres so far in 2021, according to Calfire.

On December 30, the Marshall fire in Colorado spread to about 6,000 acres. Nearly 1,000 structures were destroyed and more than 100 buildings were damaged. The fire might be the most destructive in the state’s history. Karen Clark & Co. estimates $1 billion in insured losses.

2020: In 2020 there were 58,950 wildfires compared with 50,477 in 2019, according to the National Interagency Fire Center. About 10.1 million acres were burned in 2020, compared with 4.7 million acres in 2019. Six of the top 20 largest California wildfires fires occurred in 2020, according to CalFire’s list.

In August a series of lightning strikes started hundreds of fires across Northern California. Dubbed the August Complex Fire, they are the largest fires in California’s history, together burning 1.03 million acres in seven counties and continuing into November. Another fire, the SCU Lightning Complex Fire, located in five counties in northern California near San Francisco, is the third largest fire on record in the state, burning almost 400,000 acres. The LNU Lightning Complex Fire was nearly as large as the SCU fire. It spanned five counties and caused $2 billion in insured losses, according to Aon. The North Complex Fire, encompassing three counties, burned 319,000 acres and was the 6^th largest fire in the state’s history. The SQF Complex Fire was the 18th largest California fire, burning 171,000 acres. The CZU Fire burned 86,500 acres and caused $2.4 billion in insured losses, according to Aon.

On September 28 a state of emergency was declared in California in response to the wildfires that burned through Napa, Sonoma and Shasta Counties, where tens of thousands were forced to evacuate. In October, the Glass Fire in Napa County and Sonoma County burned about 67,500 acres and destroyed 1,555 structures. State authorities ordered 70,000 residents of Sonoma and Napa Counties to evacuate, including the entire city of Calistoga in Napa Valley. The Glass Fire caused $2.9 billion in insured losses, according to Aon. The Creek Fire in Fresno and Madera counties has burned almost 400,000 acres into November, destroying 850 structures.

2019: In 2019 there were 50,477 wildfires compared with 58,083 wildfires in 2018, according to the National Interagency Fire Center (NIFC). About 4.7 million acres were burned in 2019 while there were 8.8 million acres burned in 2018. In late October significant fires broke out throughout California, leading to the evacuation of more than 200,000 people and the declaration of a state of emergency.

The Kincade Fire in Sonoma County ignited on October 23, and burned about 78,000 acres—an area more than twice the size of the city of San Francisco. According to CalFire, 374 buildings were destroyed, and 60 more were damaged.

The Getty Fire in Los Angeles broke out on October 28, fueled by strong Santa Ana winds, with wind gusts up to 80 miles an hour and burned 745 acres.

In Ventura County, the Maria Fire began on October 1 and burned 10,000 acres and destroyed four structures. The Ranch Fire, ignited November 3, burned 2,500 acres.

2018: In 2018 there were 58,083 wildfires, compared with 71,499 wildfires in 2017, according to the NIFC. About 8.8 million acres were burned in 2018, compared with 10 million in 2017. The Mendocino Complex Fire broke out on July 27 in Northern California and grew to be the largest fire state history to date, with 459,000 acres burned. The Carr Fire, which broke out on July 23 in Northern California, was the 8th most destructive fire in the state’s history to date. Eight fatalities are attributed to the fire, and 1,614 structures were destroyed. Aon estimates that insured losses from the Carr Fire were $1.3 billion in dollars when it occurred and in 2020 dollars, making it the tenth-costliest wildfire in the United States.

The Camp Fire broke out in Butte County, California, on November 8 and became the deadliest and most destructive fire on record in the state. According to Cal Fire statistics 85 people perished. About 153,000 acres were burned and 18,800 structures were destroyed. Aon estimates that insured losses from the Camp Fire totaled $10.0 billion in dollars when it occurred ($10.3 billion in 2020 dollars) and was the costliest wildfire on record.

The Hill and Woolsey Fires started on November 8. The Woolsey Fire burned about 97,000 acres, according to Cal Fire. It destroyed about 1,600 structures and killed three people. Aon estimates that insured losses from the Woolsey Fire totaled $4.2 billion when it occurred ($4.3 billion in 2020 dollars), making it the third-costliest wildfire in the United States. The Hill Fire burned about 4,500 acres and destroyed four structures.

In response to the soaring cost of wildfires in 2018, which could add up to more than $17 billion when all losses are tallied, California enacted legislation to form a $21 billion wildfire insurance fund designed to cover California utility companies for some of the losses they could incur when they pay victims of fires that their equipment caused. In May 2019 the California Department of Forestry and Fire Protection (CalFire) announced that the Camp Fire—the deadliest and costliest wildfire in U.S. history—was caused by electrical transmission lines owned by Pacific Gas and Electric (PG&E). The fund would prevent the state from having to bail out utilities facing bankruptcy, removing the burden from taxpayers. The California Earthquake Authority (CEA), which currently purchases reinsurance for earthquakes that occur in the state, will handle administrative responsibility for the fund. Utilities will contribute to the fund, while the state will raise 50 percent of the $21 billion via bond sales. According to Artemis, the fund could operate as a risk pool where electric utility exposure could be handled by insurance, reinsurance or insurance-linked securities. By the end of July 2019 all three of California’s utilities had agreed to join and commit funds to the plan.

2017: In 2017 there were 71,499 wildfires, compared to 65,575 wildfires in 2016, according to the NIFC. About 10 million acres were burned in 2017, compared with 5.4 million in 2016. The number of acres burned in 2017 was higher than the 10-year average. From October 6 to October 25, eight counties in Northern California were hit by a devastating wildfire outbreak that caused at least 23 fatalities, burned 245,000 acres and destroyed more than 8,700 structures.

The Tubbs Fire began on October 8 and destroyed almost 37,000 acres and 5,600 structures and claimed 22 victims. Aon estimates that insured losses from the Tubbs Fire totaled $8.7 billion when it occurred ($9.1 billion in 2020 dollars), making it the second-costliest wildfire in the United States. The Atlas Fire also began on October 8 and consumed 52,000 acres and destroyed 120 structures. Six people perished in the Atlas Fire. According to Aon the Atlas Fire caused insured losses of $3.0 billion when it occurred or $3.1 billion in 2020 dollars, making it the fifth-costliest U.S. wildfire. The Thomas Fire was ignited on December 4. It burned 282,000 acres and destroyed 1,063 structures. Aon estimates that insured losses from the Thomas Fire totaled $2.3 billion when it occurred and $2.4 billion in 2020 dollars. The Thomas Fire was the sixth-costliest on record in the United States.

Annual Number of Acres Burned in Wildland Fires, 1980-2020

 

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*2004 fires and acres do not include state lands for North Carolina.

Source: National Interagency Fire Center.

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FireLine®, Verisk’s wildfire risk management tool, assesses wildfire risk at the address level using advanced remote sensing and digital mapping technology. The three primary factors considered in analyzing wildfire risk are distribution of vegetative fuel, steepness of slope and degree of access for firefighting equipment. FireLine assigns a wildfire hazard score for each factor plus a cumulative score, on a scale from negligible to extreme risk. The following chart ranks the most wildfire-prone western U.S. states by high to extreme wildfire risk as of 2021. According to Verisk estimates, in California, there were more than 2 million properties at high to extreme wildfire risk in 2021, the largest number of properties of any U.S. state.