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 6th 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

 

*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.

States At High To Extreme Wildfire Risk, 2021 (1)

 

Rank State Estimated number of
properties at risk
Rank State Percent of
properties at risk
1 California 2,040,600 1 Montana 29%
2 Texas 717,800 2 Idaho 26
3 Colorado 373,900 3 Colorado 17
4 Arizona 242,200 4 California 15
5 Idaho 175,000 5 New Mexico 15
6 Washington 155,500 6 Utah 14
7 Oklahoma 153,400 7 Wyoming 14
8 Oregon 147,500 8 Arizona 9
9 Montana 137,800 9 Oklahoma 9
10 Utah 136,000 10 Oregon 9
11 New Mexico 131,600 11 Texas 7
12 Nevada 67,100 12 Nevada 6
13 Wyoming 36,800 13 Washington 5

(1) As of October 2021.

Source: Verisk Wildfire Risk Analytics used data from FireLine®, Verisk's wildfire risk management tool.

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Wildfires By State, 2021

 

State Number of fires Number of acres burned 
Alabama 1,040 22,055
Alaska 384 253,357
Arizona 1,773 524,428
Arkansas 378 17,003
California 9,260 2,233,666
Colorado 1,017 48,195
Connecticut 60 127
Delaware 0 0
District of Columbia 0 0
Florida 2,262 105,475
Georgia 2,139 11,108
Hawaii 1 40,000
Idaho 1,332 439,600
Illinois 29 219
Indiana 34 836
Iowa 187 7,950
Kansas 55 163,982
Kentucky 723 22,859
Louisiana 507 10,303
Maine 636 377
Maryland 112 1,162
Massachusetts 588 1,439
Michigan 435 9,289
Minnesota 2,065 69,405
Mississippi 922 21,037
Missouri 1,531 40,262
Montana 2,573 747,678
Nebraska 785 27,294
Nevada 565 123,427
New Hampshire 280 96
New Jersey 906 6,652
New Mexico 672 123,792
New York 137 550
North Carolina 5,151 25,838
North Dakota 946 49,347
Ohio 524 1,415
Oklahoma 1,727 113,235
Oregon 2,202 828,777
Pennsylvania 1,350 2,892
Puerto Rico 0 0
Rhode Island 99 178
South Carolina 630 7,337
South Dakota 868 43,620
Tennessee 550 4,937
Texas 5,576 168,258
Utah 1,085 60,863
Vermont 90 157
Virginia 567 6,696
Washington 1,863 674,222
West Virginia 752 7,504
Wisconsin 1,040 2,159
Wyoming 540 53,496
United States (1) 58,948 7,124,554

(1) Includes Puerto Rico. Totals for the United States do not match totals shown elsewhere by the National Interagency Fire Center due to the use of different exhibits.

Source: National Interagency Fire Center.

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Top 10 States For Wildfires Ranked By Number Of Fires And By Number Of Acres Burned, 2021

 

Rank State Number of fires Rank State Number of acres burned
1 California 9,260 1 California 2,233,666
2 Texas 5,576 2 Oregon 828,777
3 North Carolina 5,151 3 Montana 747,678
4 Montana 2,573 4 Washisngton 674,222
5 Florida 2,262 5 Arizona 524,428
6 Oregon 2,202 6 Idaho 439,600
7 Georgia 2,139 7 Alaska 253,357
8 Minnesota 2,065 8 Texas 168,258
9 Washington 1,863 9 Kansas 163,982
10 Arizona 1,773 10 New Mexico 123,792

Source: National Interagency Fire Center.

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Top 10 Costliest Wildland Fires In The United States (1)

($ millions)

      Estimated insured loss
Rank Year Name Dollars when occurred In 2021 dollars (2)
1 2018 Camp Fire $10,000 $10,750
2 2017 Tubbs Fire 8,700 9,560
3 2018 Woolsey Fire 4,200 4,520
4 1991 Oakland Fire (Tunnel) 1,700 3,350
5 2017 Atlas Fire 3,000 3,300
6 2020 Glass Fire 2,950 3,070
7 2020 CZU Lightning Complex Fire 2,500 2,600
8 2017 Thomas Fire 2,250 2,470
9 2020 LNU Lightning Complex Fire 2,250 2,340
10 2007 Witch Fire 1,600 2,080

(1) Includes losses sustained by private insurers and government-sponsored programs such as the National Flood Insurance Program. Includes events that occurred through 2021. All fires on this list occurred in California. Includes Puerto Rico and the U.S. Virgin Islands. Ranked on losses in 2021 dollars. Subject to change as loss estimates are further developed. As of Feburary 3, 2022.
(2) Adjusted for inflation by Aon using the U.S. Consumer Price Index.

Source: Aon.

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Top 10 Largest California Wildfires (1)

 

Rank Fire name (cause) Date County Acres Structures Deaths
1 August Complex (Lightning) August 2020 Mendocino, Humboldt, Trinity, Tehama, Glenn, Lake, and Colusa 1,032,648 935 1
2 Dixie (Under investigation) July 2021 Butte, Plumas, Lassen, Shasta, and Tehama 963,309 1,329 1
3 Mendocino Complex (Human related) July 2018 Colusa, Lake,Mendocino and Glenn 459,123 280 1
4 SCU Lightning Complex (Lightning) August 2020 Stanislaus, Santa Clara, Alameda, Contra Costa, and San Joaquin 396,624 222 0
5 Creek Fire (Undetermined) September 2020 Fresno and Madera 379,895 853 0
6 LNU Lightning Complex (Lightning/arson) August 2020 Sonoma, Lake, Napa, Yolo and Coluso 363,220 1,491 6
7 North Complex (Lightning) August 2020 Butte, Plumas and Yuba 318,935 2,352 15
8 Thomas (Power lines) December 2017 Ventura and Santa Barbara 281,893 1,063 2
9 Cedar (Human related) October 2003 San Diego 273,246 2,820 15
10 Rush (Lightning) August 2012 Lassen 271,911 CA /
43,666 NV
0 0

(1) As of October 25, 2021.

Source: Calfire.

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Top 10 Most Destructive California Wildfires (1)

 

Rank Fire name and cause Date County Acres Structures Deaths
1 Camp Fire (Power lines) November 2018 Butte 153,336 18,804 85
2 Tubbs (Electrical) October 2017 Napa and Sonoma 36,807 5,636 22
3 Tunnel - Oakland Hills (Rekindle) October 1991 Alameda 1,600 2,900 25
4 Cedar (Human related) October 2003 San Diego 273,246 2,820 15
5 North Complex (Lightning) August 2020 Butte, Plumas and Yuba 318,935 2,352 15
6 Valley (Electrical) September 2015 Lake, Napa and Sonoma 76,067 1,955 4
7 Witch (Power lines) October 2007 San Diego 197,990 1,650 2
8 Woolsey (Electrical) November 2018 Ventura 96,949 1,643 3
9 Carr (Human related) July 2018 Shasta County and Trinity 229,651 1,614 8
10 Glass Fire (Undetermined) September 2020 Napa and Sonoma 67,484 1,520 0

(1) As of October 25,2021.

Source: Calfire.

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Top 10 Deadliest California Wildfires (1)

 

Rank Fire name and cause Date County Acres Structures Deaths
1 Camp Fire (Power lines) November 2018 Butte 153,336 18,804 85
2 Griffith Park (Unknown) October 1933 Los Angeles 47 0 29
3 Tunnel - Oakland Hills (Rekindle) October 1991 Alameda 1,600 2,900 25
4 Tubbs (Electrical) October 2017 Napa and Sonoma 36,807 5,643 22
5 North Complex (Lightning) August 2020 Butte, Plumas and Yuba 318,935 2,352 15
6 Cedar (Human related) October 2003 San Diego 273,246 2,820 15
7 Rattlesnake (Arson) July 1953 Glenn 1,340 0 15
8 Loop (Unknown) November 1966 Los Angeles 2,028 0 12
9 Hauser Creek (Human related) October 1943 San Diego 13,145 0 11
10 Inaja (Human related) November 1956 San Diego 43,904 0 11

(1) As of October 22, 2021.
(2) Numbers not final.

Source: Calfire.

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