NaturalHazards.org

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Wildland fire on the Colorado Front Range.

perilous planet
 for more wildland fire photography.



Other Resources:

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Fire in America: A Cultural History of Wildland Fire and Rural Fire (Stephen J. Pyne)

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Mapping Wildfire Hazards and Risks (R. Neil Sampson, R. Dwight Atkinson, Joe W. Lewis)

 

WHAT is wildland fire?

Like floods in stream systems, wildland fire is a natural occurrence in many ecosystems. Actually, fire plays an important role in maintaining the health of some ecosystems, such as prairies and oak savannas. However, when fire threatens human life or property, it is considered a natural hazard. Besides the obvious threat of hot flames causing materials to burn, fire can also send vast amounts of ash into the atmosphere, which can inhibit plant growth, reduce visibility, and interfere with the breathing of people and other animals. It can also set the stage for slope failures and flooding by destroying vegetation, which leaves slopes vulnerable to heavy rains long after the fire has burned out. Wildland fires, which are large fires often covering many square miles (kilometers) that can burn for many days, are most frequently ignited by lightning and sometimes by human activities, such as cigarette smoking and campfires. Wildland fires can generate hurricane-force winds and can quickly climb up steep terrain, such as mountain slopes. In fact, the steeper the slope, the faster a fire is likely to burn.


WHERE does wildland fire occur?

In the Northern Hemisphere, wildland fires most commonly occur in southern grasslands and southern needleleaf forests, where vegetation is abundant, humidity is usually low, and temperatures are warm. Although fires occur less frequently in colder and wetter climates, they are still a threat wherever vegetation grows. In the United States, most wildland fires occur in the western region that extends from the Rocky Mountain Front Range to the Pacific Coast. In canyons and valleys, wildland fire can be particularly dangerous because the narrow canyons and valleys concentrate winds, which can increase a fire's intensity while providing few escape routes. In Colorado and California, the Chinook winds and Santa Ana winds are often associated with these topography driven wildland fires.

Quick Fact:
In the year 2002, over 50,000 fires burned almost 5 million acres in 10 western states in the U.S. Over 1800 homes were damaged or destroyed. Although this is the yearly average number of fires, it is over twice the yearly average number of acres.


WHEN does wildland fire occur?

Fire is a potential hazard whenever vegetation becomes dry. This often occurs as the result of drought during the growing season. Since lightning is most common during the growing season, dry weather prior to thunderstorms during Spring, Summer, or Fall increases the risk of a wildland fire ignited from lightning. Wildland fires are also more likely when trees become diseased, which can be caused by insects, fungus, pollution, or any combination of these factors. In the western United States, climate change is likely increasing the populations of pine and spruce beatles that are infesting the mountainous evergreen forests with a deadly fungus and causing high rates of mortality. Because of this, the western United States is facing one of the highest wildland fire threats in history.


HOW do we cope with wildland fire?

Protecting lives and property from wildland fire can be a relatively easy task, with a little education and planning. Fire-resistant roofs, vegetation-free safety zones around buildings, adequate water supplies, and planned escape routes can greatly improve the likelihood of surviving a fire with minimal loss. Of course, building in areas not prone to wildland fires can also significantly reduce the threat of these natural hazards. Since fires most frequently occur during periods of low precipitation, weather forecasting serves an important role in fire mitigation by alerting protection agencies and citizens of potential future dry periods. In the western United States, the National Forest Service, state agencies, county agencies, and even local municipalities have dedicated fire fighting teams that control wildland fires and protect property during fire season. During the low-risk season, these teams perform prescribed burns to reduce future wildland fire risk. Satellite imagery is used to assist wildland fire fighting efforts by identifying areas of diseased or dead trees that may be difficult to detect from the ground.

Quick Fact:
The U.S. government spends hundreds of millions of dollars annually to control wildland fires.


WHO has more information on wildland fire?