Background
Fire is an important disturbance process in almost every ecosystem in the world1. However, catastrophic wildfires have claimed numerous lives and destroyed countless homes2. Therefore, understanding wildfire risk is of profound social and economic importance.
Heightened wildfire risk is driven by a number of factors, such as climate change, decades of fire suppression, and the expansion of residential developments into highly vegetated areas . The area with the greatest wildfire risk is known as the wildland-urban interface (WUI). The WUI is the area where human structures intermingle with flammable vegetation. WUI areas experience higher wildfire risk due to greater potential for human ignitions, the presence of flammable invasive species, and limited accessibility for firefighters.
How to Use this Tool
Below are four interactive maps showing:
- The percent of each state categorized as WUI for the years 1990, 2000, 2010, and 2020
- The number of wildfire fatalities in each state between 1999 and 2020
- The number of structures damaged and destroyed by wildfires in each state between 1999 and 2020
- The total cost to suppress wildfires in each state between 1999 and 2020
To use each map, you can zoom in or out and click on your area of
interest to see state-level statistics.
WUI Growth
In recent decades, the United States WUI has grown substantially. In
1990, the WUI only covered 7.2% (579,172 km2) of the total
land area of the conterminous United States. In 2020, that number had
grown to 9.4% (758,503 km2). Additionally, 29.5% (29.9
million) of all houses in the United States were in the WUI in 1990. In
2020, more than 31.5% (43.9 million) of houses were in the WUI3.
Figure 1. An interactive map showing the percent of each state
that is categorized as wildland-urban interface (WUI) across the United
States in 1990, 2000, 2010, and 2020 [Data
source].
Wildfire Fatalities
Between 1999 and 2020, 543 people lost their lives to wildfires. Most
fatalities occurred in California, with 287 deaths from wildfires.
Arizona and Texas had 25 or more fatalities. Colorado, Oregon,
Wisconsin, and Tennessee had more than 15 fatalities.
Figure 2. An interactive map showing the number of responder and
public fatalities from wildfires between 1999 and 2020 by state across
the continental United States [Data
source].
Building Loss to Wildfires
Between 1999 and 2020, wildfires destroyed over 108 thousand
structures and damaged over 73 thousand. California experienced the
greatest structure loss, with over 51 thousands structures damaged and
over 66 thousand structures destroyed by wildfires during this time.
Oklahoma and Oregon experienced also substantial structure loss, with
over 4,000 structures damaged and 4,000 destroyed.
Figure 3. An interactive map showing the number of structures
damaged and destroyed by wildfires between 1999 and 2020 by state across
the continental United States [Data
source].
Wildfire Suppression Costs
Between 1999 and 2020, wildfires required over $30.6 billion to
suppress. The majority of these suppression costs were concentrated in
the western U.S., particularly California. However, eastern U.S. states
such as Florida, North Carolina, Texas, and Georgia required over $100
million to suppress wildfires during this period.
Figure 4. An interactive map showing the cost to suppress
wildfires between 1999 and 2020 by state across the continental United
States [Data
source].
What Can We Do?
Wildfire risk management is crucial for everyone living in and near wildland vegetation. Property owners, forest managers, and the general public should be aware of this risk and take precautionary measures to avoid serious loss from wildfire. Communities can work together to inform one another about the risk of flammable vegetation near homes and take action to reduce the associated risk.
One way that land owners and forest managers can reduce wildfire risk is through the systematic and intentional use of prescribed fire. Prescribed fire has been shown to mitigate wildfire risk by reducing previously accumulated fuels that would otherwise allow wildfires to spread toward buildings4. Burning can also promote ecosystem health by improving nutrient cycling, creating a more diverse habitat for wildlife, and facilitating native plant growth5.
Another way to mitigate wildfire risk is by creating defensible spaces around structures, thereby placing a buffer between flammable vegetation and homes6. Homeowners can remove debris and flammable materials close to their homes. Builders can also utilize fire-resistant materials in the construction of new homes7.
Land owners, forest managers, and policymakers should collaborate in
order to protect our lives and property from the threat of wildfire.
