Wildfires

Fire Danger & Management | Wildfire

 

Table of Contents


 

What does wildfire do?

Low-intensity fire burning along the forest floor

Low flames along the edge of a wildfire, leaving trees unharmed while consuming forest litter as it progresses. (USFS/Thumm 2015)

wildfire allowed to burn starts as a naturally-caused, low intensity wildland fire. In northern Arizona, lightning strikes are typically the natural cause for these types of fires. Such wildfires may be allowed to burn to put fire back into the ecosystem to reduce fire danger and restore forest health. Fire managers allow the managed fire to run its natural course within well defined and maintained perimeters.

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Wildfire?! Is the forest burning down?

Small pine trees on backdrop of smoking, blackened forest floor

Demonstrating a wildfire's low intensity, the heat and flames of this wildfire's passage did little damage to these small pines trees while cleaning up the forest floor directly below them. (USFS/Soltesz 2015)

When the humidity, moisture, and weather conditions are favorable, a managed wildland fire is a slow-burning surface fire. The flames are low to the ground and the fire spreads slowly across the forest floor. This type of fire safely consumes dead and down logs, fallen leaves and pine needles, low hanging branches, dried grasses, and small trees. Larger trees are generally unharmed, and vegetation will soon return to the area.

As a low-intensity managed wildfire crawls along, it follows its own natural paths. As a result, some areas may be untouched while others burn, creating a mosaic pattern across the forest floor. As a result, some vegetation is burned off while other vegetation remains to continue growing and reseeding. This mosaic burn pattern is beneficial to the forest health by encouraging ecological diversity.

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Why let a fire burn instead of putting it out?

Edge of a managed wildfire, burning dead logs and pine needles.

The edge of a wildfire crawling along the forest floor, burning pine needles, dead logs, and debris in its path while sparing larger trees. (USFS/Soltesz 2015)

Fire is an intrinsic part of the landscape of the Southwest. Historically, fire would return to an area every two to ten years. Unlike wetter climates, dead wood and vegetation do not decompose well in northern Arizona's dry climate. Vital nutrients, such as nitrogen, remain locked up in dead wood and vegetation until decomposition returns these nutrients to the soil. In this region, it is fire that serves to break down dead wood and vegetation, releasing the vital nutrients new grasses, flowers, and other vegetation need to thrive.

In addition to the ecological benefits, allowing low intensity wildfires to burn reduces the risk of severe wildfires in the future. In the right conditions pine needles, dead logs, and other forest litter burn slowly. However, in the wrong conditions, these materials serve as fuels to make a severe wildfire burn hotter, faster, and with greater intensity, making such fires even more difficult to contain. Reducing potential fuels helps reduce severe wildfires that endanger the forest, property, and lives.

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How are natural fires suppressed?

Helitak helicopter taking off from command center to perform aerial ignitions (2015)

Helitak helicopter taking off from command center to perform aerial ignition operations (USFS/Simmons 2015)

When a naturally-caused wildland fire starts, fire managers make an assessment to determine if conditions are favorable for full suppression of the wildfire or allowing it to burn. Weather forecasts, soil and vegetation moisture, the landscape surrounding the wildfire, and potential risks are all considered in this assessment. If conditions are good for the wildfire, fire managers determine a perimeter for the fire, and identify areas that must be protected. Crew perform burnout operations in strategic areas to manage how and where the fire moves through the forest, allowing the fire to take its course while protecting property and wildlife.

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What are burnout operations?

Crew performing burnout operations along a managed wildfire perimeter.

Crew performing burnout operations along a managed wildfire perimeter. (USFS/Simmons 2015)

Crews apply fire along the forest floor to burn off fuels. This is often done in advance of the wildfire to enforce a boundary for the fire, keeping it within the perimeter or guiding it around a sensitive area. Burnout operations may also be performed in areas where limiting the fire severity or smoke is critical, such as along hillsides or near powerlines that are sensitive to heavy smoke.

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What are backburns?

Hilltop treated with fire, burning down from top in advance of the Camillo Fire.

Aerial ignition operations were used to start the backburn on this hill as a fire approached. (USFS/Rice 2015)

Backburning is a technique for burning an area in the opposite direction the flames want to go, such a on hills. Hills have an inherit risk of increased fire severity if the fire is allowed to move up the hillside. By igniting a fire at the top of the hill, the fire can only move downhill, keeping the fire's spread slow and low intensity. With fuels burned off the hillside, when the wildfire reaches the hill, it will move around the hill instead of up the hill.

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What is the difference between a wildfire and a prescribed burn?

A prescribed burn is planned in advance, with specific conditions set appropriate to the project. Crews ignite and manage the burn, and planned burn activity may be cancelled if the wind, moisture, temperature, and other required conditions are not met. Prescribed burn operations have a planned start and completion date. Learn more about prescribed burns.

A wildfire is an unplanned, naturally occurring wildland fire. If conditions are favorable, the wildfire is allowed to continue naturally, burning instead of being supressed. While burn operations may be used to keep the fire in the planned perimeter and away from sensitive areas, the fire itself is allowed to progress naturally through the management area. Wildfires do not have a planned end date.

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Sources of Fires 

It is important to recognize that human-caused wildfires are in the minority when it comes to sources of ignition. As you can see from the 40-Year Fire Timeline below, lightning has been the major source of wildfires on the Coconino National Forest, so wildfires are simply a part of the ponderosa pine ecosystem that we live in. Click on the image below to see a larger version.

40 Year timeline showing that the major source of wildfires is lightning.

 

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What should I expect?

Wildfires grow, increasing in size but not severity. Smoke will be noticeable, especially during burn operations. However, smoke from wildfire is much lighter than from a severe wildfire. Motorists should drive with care in the area near a fire. Smoke may reduce visibility and fire personnel may be working on or near the road. Wildfires move and burn slowly, and efforts are made to protect buildings, property, sensitive wildlife habitats, and people.

Because these types of fires are allowed to burn naturally, they do not have planned end dates. As long as conditions permit and objectives are being met, crews will continue to actively manage the fire.

Depending on the extent, longevity, and other factors, there may be road or lands closures. During a fire, closures will be posted on the InciWeb incident information page, and under Alerts & Notices on Coconino National Forest site. Major closures of lands will posted on Forest Orders.

Wildfires burn continuously for at least several days, and smoke may impact communities, sometimes unexpectedly, while the fire continues to burn. If you are affected by smoke from a fire on the Coconino National Forest, submit Smoke Report to share your observation, experience, or complaint, and help us get this information to Fire Management Officers and the Leadership Team.

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Photos

Photo gallery from the large, but otherwise typical, Camillo Fire [Flickr]. This was a lightning-caused fire started southeast of Mormon Lake (20 miles south of Flagstaff, Arizona) in June 2015.

See more photos from managed wildfires in our Wildfires collection on the Coconino National Forest's Flickr photo site.

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Additional Resources and Information

Learn More About Wildfire

Coconino National Forest Information

General Information

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