Background on: Wildfires

 
Overview

Fire plays an important role in the life of a forest, clearing away dead wood and undergrowth to make way for younger trees, but the risk wildfires pose to people and property is growing as more people move into forested areas once largely uninhabited. These areas, known as the Wildland-Urban Interface (WUI), contain about 44 million houses in the lower 48 states, according to the U.S. Forest Service.

Rising temperatures are also believed to contribute to large, destructive blazes. Warmer weather contributes to wildfire conditions in several ways: dryer and more combustible vegetation, more frequent lightning strikes, an extended fire season; and more intense winds.

Harvard School of Engineering and Applied Sciences researchers have concluded that by 2050 the number of wildfires in the West could rise by 50 percent, and across the U.S. the number would double.

 
Insured wildfire losses

Damage caused by fire and smoke are covered under standard homeowners, renters and business owners insurance policies and under the comprehensive portion of an auto insurance policy. Water or other damage caused by fire fighters to extinguish the fire is also covered under these policies. In California, the California FAIR Plan covers residential and commercial properties located in brush and wildfire areas. Properties in those areas are subject to higher rates due to increased risk of fire. 

 
Causes of wildfires

As many as 90 percent of wildland fires in the United States are caused by humans, 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.

 
Wildfire prevention and mitigation

Researchers are discovering that embers blown by the wind during wildfires cause most of the fires that burn homes. Also, homes that are less than 15 feet apart are more likely to burn in clusters. In such cases, fire is often spread by combustible fences and decks connected to houses, a study by the Insurance Institute for Business & Home Safety (IBHS) found.

Among the preventive features recommended in the IBHS study were noncombustible siding, decking and roofing materials; covered vents; and fences not connected directly to the house. In addition, combustible structures in the yard such as playground equipment should be at least 30 feet away from the house and vegetation 100 feet away.

 
Properties at risk for wildfires

According to Verisk’s 2017 Wildfire Risk Analysis 4.5 million U.S. homes were identified at high or extreme risk of wildfire, with more than 2 million in California alone.

 
Charts and graphs

 
Total Potential Exposure To Wildfire Damage By Risk Category, 2014 (1)

($ billions)

State Low Moderate High Very high
Arizona $9.64 $0.98 $1.76 $1.57
California 75.84 61.92 89.35 16.10
Colorado 18.63 11.53 14.58 13.91
Idaho 9.20 5.56 3.71 2.62
Montana 14.63 4.43 2.29 2.40
Nevada 4.24 5.19 4.57 0.16
New Mexico 11.65 4.62 7.07 2.46
Oklahoma 31.92 16.77 0.03 0.00
Oregon 8.24 9.49 11.91 3.20
Texas 59.53 147.68 48.26 6.33
Utah 2.85 3.93 0.77 0.01
Washington 84.07 18.08 2.88 0.51
Wyoming 3.68 2.62 0.49 0.33
Total, states shown $331.27 $292.81 $187.66 $49.61

(1) Reconstruction value of single-family residences at risk.

Source: CoreLogic, Inc., a data and analytics company.

View Archived Tables

 
Top 10 Most Wildfire Prone States, 2017

By households By percent
of households
Rank State Households at high
or extreme risk
from wildfires (1)
Rank State Percent of households
at high or extreme
risk from wildfires
1 California  2,044,800 1 Montana 28%
2 Texas 715,300 2 Idaho 26
3 Colorado 366,200 3 Colorado 17
4 Arizona 234,600 4 California   15
5 Idaho 171,200 5 New Mexico 14
6 Washington 154,900 6 Utah 14
7 Oklahoma 152,900 7 Wyoming 14
8 Oregon 148,800 8 Oklahoma 9
9 Utah 133,100 9 Oregon 9
10 Montana 133,000 10 Arizona 8

(1) Number of households is based on data from the 2010 U.S. Census.

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

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Wildfire Losses In The United States, 2008-2017 (1)

(2017 $ millions)

(1) Adjusted for inflation by Munich Re based on the Consumer Price Index.

Source: © 2018 Munich Re, NatCatSERVICE.

View Archived Graphs

 
Natural Catastrophe Losses In The United States, 2017 (1)

($ millions)

Event  Number of events (2) Fatalities Overall losses Insured losses (3) 
Severe thunderstorm 50 85 $25.4 $18.2
Winter storms and cold waves 13 24 2.2 1.2
Flood, flash flood 12 14 0.4 0.1
Earthquake and geophysical 2 1 minor minor
Tropical cyclone 5 170 123.0 49.1
Wildfire, heat waves and drought 21 62 14.3 9.5
Total 103 356 $165.3 $78.0

(1) As of January 2018.
(2) Events that have caused at least one fatality or losses of $3 million or more.
(3) Based on property losses including, if applicable, agricultural, offshore, marine, aviation and National Flood Insurance Program losses and may differ from data shown elsewhere.

Source: Property Claim Services®,  a unit of ISO®, a Verisk Analytics® business, © 2018 Munich Re, NatCatSERVICE.

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Top 10 States For Wildfires Ranked By Number Of Fires And By Number Of Acres Burned, 2017

Rank State Number of fires Rank State Number of acres burned
1 Texas 9,827 1 Montana 1,366,498
2 California 9,560 2 Nevada 1,329,289
3 North Carolina 5,125 3 California 1,266,224
4 Georgia 3,929 4 Texas 734,682
5 Missouri 3,398 5 Oregon 714,520
6 Florida 3,280 6 Idaho 686,262
7 Mississippi 2,775 7 Alaska 653,023
8 Montana 2,422 8 Oklahoma 502,625
9 Arizona 2,321 9 Kansas 476,306
10 Oregon 2,049 10 Arizona 429,564

Source: National Interagency Fire Center.

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

($ millions)

      Estimated insured loss
Rank Date Name, Location Dollars when occurred In 2017 dollars (2)
1 Nov. 8-25, 2018 Camp Fire, CA (3) (3)
2 Oct. 8-20, 2017 Tubbs Fire, CA (3) (3)
3 Nov. 8-22, 2018 Woolsey Fire, Ca (3) (3)
4 Oct. 8-20, 2017 Atlas Fire, CA (3) (3)
5 Dec 4 - 23, 2017 Thomas Fire, CA (3) (3)
6 Oct. 20-21, 1991 Oakland Hills Fire, CA $1,700 $2,788
7 Oct. 21-24, 2007 Witch Fire, CA 1,300 1,517
8 Jul. 23-Aug. 30, 2018 Carr Fire, CA (3) (3)
9 Oct. 25-Nov. 4, 2003 Cedar Fire, CA 1,060 1,386
10 Oct. 25-Nov. 3, 2003 Old Fire, CA 975 1,275

(1) Property coverage only for catastrophic fires. Effective January 1, 1997, ISO's Property Claim Services (PCS) unit defines catastrophes as events that cause more than $25 million in insured property damage and that affect a significant number of insureds and insurers. From 1982 to 1996, PCS used a $5 million threshold in defining catastrophes. Before 1982, PCS used a $1 million threshold. As of December 11, 2018.
(2) Adjusted for inflation through 2017 by the Insurance Information Institute using the GDP implicit price deflator.
(3) Loss estimate not yet available from PCS, but a relative ranking is provided.

Source: The Property Claim Services® (PCS®) unit of ISO®, a Verisk Analytics® company, U.S. Bureau of Labor Statistics.

View Archived Tables

 
Additional resources

Verisk Insurance Solutions' FireLine State Risk Report

National Interagency Fire Center

Headwaters Economics - The Rising Cost of Wildfire Protection

Insurance Institute for Business & Home Safety – Wildfire resources

National Fire Prevention Administration - Wildfire safety tips

Wildfire Hazard Potential Map

Cal Fire's ReadyforWildfire.org

© Insurance Information Institute, Inc. - ALL RIGHTS RESERVED

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