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.

In 2021, there were 58,985 wildfires, compared with 58,950 in 2020, according to the National Interagency Fire Center. About 7.1 million acres were burned in 2021, compared with 10.1 million 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.

Annual Number of Acres Burned in Wildland Fires, 1980-2021

 

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

Source: National Interagency Fire Center.

View Archived Graphs

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.