Wildfires

Wildfires can move and burn large areas at an incredible speed leading to significant damage to both natural areas and property. In the United States, they are becoming more frequent and intense in some areas and proximity to wildfires may reduce property values.


Aaron Baker

Jul 23, 2021 • Updated Mar 14, 2022 • 6 min read

Find recent wildfire data and interactive fire maps here

Wildfires are difficult to prevent and can be as destructive as hurricanes, floods, and tornadoes. Wildfires can move and burn large areas at an incredible speed leading to significant damage to both natural areas and property. In the United States, they are becoming more frequent and intense in some areas and proximity to wildfires may reduce property values. In addition, wildfires can lead to significant loss of life, their smoke and particulate pollution can negatively impact human health, and their damage to infrastructure and services can cause personal and economic disruption.

Overview#

Wildfires are either unplanned or prescribed burn fires in natural areas including forests, grasslands, and prairies. Unplanned wildfires start from lightning or human activity including unattended campfires, debris burning, sparks from vehicles, equipment use and malfunctions, power lines, discarded cigarettes, and intentional acts of arson. An analysis of over 1.5 million wildfires between 1992 and 2012 published in the Proceedings of the National Academy of Sciences found that nearly 85% were caused by humans. The researchers then estimated that humans were responsible for about 40,000 wildfires per year in the US.

Prescribed burns (sometimes also referred to as controlled burns), on the other hand,__are designed to meet specific forest management goals that include reducing the volume of combustible material and minimizing the spread of insects and disease. Prescribed burns can be used to control the spread of unplanned wildfires and reduce the intensity of unplanned wildfires when they do occur.

Wildfires can spread quickly and cause devastating damage to wildlife, natural areas, and communities. These types of fires are a force of nature that can be nearly as impossible to prevent and as difficult to control as hurricanes, floods, and tornadoes. The 2018 Camp Fire in northern California, caused by electrical transmission lines, burned at a rate of roughly 80 football fields per minute, caused at least 90 deaths, and destroyed 18,000 structures.

From 2000-2020, an average of about 70,600 wildfires have burned over 7 million acres each year of public and private land in the US. Between 2017 and 2020 an average of over 14,000 structures burned each year in wildfires, of which about 60% were residential homes. Most wildfires are small and only about 1% become raging destructive fires known as conflagrations. Of the 1.5 million wildfires that have occurred over the last 10 years, 224 burned more than 100,000 acres, and 14 burned more than 500,000 acres.

In the last 30 years, both the number of fires and the number of acres burned have increased. Since 2015, the US has averaged 100 more large wildfires (fires >300 acres) each year than the year before. The average number of acres burned since 2000 is more than double the average number of acres burned in the 1990s. Warmer temperatures including extreme heat; more fuel from tree die-off caused by drought, insects, and disease; earlier snowmelt; stronger winds; and less precipitation are expected to continue to increase the likelihood that fires will burn more intensely. Fires also have the potential to generate their own wind and under extreme conditions, this can accelerate the spread of a wildfire.

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While California has suffered the brunt of US wildfire destruction in recent years, Idaho and Alaska both saw more acreage burned between 1992 and 2018 than all other states. Nationally, the majority of wildfires occur in the western and southern states. The map below shows the number of wildfires per fire weather zone that burned more than 10 acres over a 34 year period between 1980-2014. Fire weather zones are small county-sized regions with similar climate, weather, and terrain characteristics.

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Economic losses from wildfires in the US have also increased. From 2007-2016 the average annual insured losses from wildfires were about $9 billion (inflation-adjusted to 2017 dollars). From 2017-2020 the average losses increased to over $15 billion per year and the 2021 wildfire season is already outpacing previous years. Insured losses only represent a fraction of the total economic impact of wildfires. For example, researchers at UC Irvine estimated a total economic loss of about $150 billion from the 2018 wildfires in California alone--primarily from the health effects of air pollution and disruption of economic supply chains.

Your Home and Wildfires#

Health and Safety#

The Centers for Disease Control (CDC) recommends several steps to prepare for wildfires including an evacuation route, emergency supplies, setting up a clean room to safely keep smoke out, and monitoring local wildfire activity. Multiple evacuation routes should be planned and practiced in advance.

Along with food, water, and medication, the CDC recommends P100 or N95 respirators to protect your lungs from particulates found in wildfire smoke. In some parts of California and the West, the average number of days per year with poor air quality from smoke is over 140. In these areas, a home HEPA filtration system that filters 99.97% of airborne particles can help maintain clean indoor air. A clean room should be large enough to fit everyone in your household, sealed off from the outside, set up with fans or air conditioners to stay cool, and equipped with an air filter system.

In addition, the EPA has specific recommendations for protecting livestock from wildfires including an evacuation plan with trailer resources and training all livestock to load onto trailers, temporary livestock shelter locations, and an evacuation kit with feed and other supplies for 7-10 days, medical records, and animal care instructions. If livestock cannot be evacuated, they recommend leaving animals in a predetermined cleared area with a lower risk of fire, leaving gates and fences open, leaving food and water for 48-72 hours, and alerting neighbors and first responders to be on the lookout for your animals.

Property Values#

An analysis of over 50,000 single residence homes in southern California found that close proximity (within 1.75 miles) to a wildfire reduced sale prices by 10% and close proximity to a second fire reduced sale prices a total of nearly 23%. Similar conclusions were made by researchers in Colorado where prices dropped about 15% within 2 miles of a wildfire and in New Mexico where prices decreased between 3-11%.

What You Can Do#

Determine the risk of fire in your community. The US Department of Agriculture provides a wildfire risk ranking by state as well as community level. For example, California, Idaho, Oklahoma, and Utah are all over 90% more likely than all other states to experience wildfires whereas Maine, Rhode Island, and the District of Columbia are all below 5%. For homes in an area with a risk of wildfires, FEMA recommends ensuring that structures have roofs with a Class A fire rating and are clear of leaves, needles, and other debris; vents and stilt foundations are screened with ⅛” metal mesh; combustible gates and fences are 5 feet or more from home; windows consisting of tempered glass; and there is at least 6 inches of vertical space between the ground and siding.

In addition, they recommend establishing three zones extending to 100 feet from a home. The nearest zone extends 5 feet from a home and would require the most vigilance, but in general, all zones should be modified by treating, clearing, or reducing natural and manmade fuels to slow the spread of wildfire.

AreaHub’s Knowledge Center is updated regularly and provides information drawing upon scientific studies and sources.

Sources#