The Wildfire Model
NCAR’s scientists, mathematicians, and software engineers have created a
computer model to study what they have learned about wildfire behavior. The
model predicts the behavior of the fire and the atmosphere as they influence
each other. Scientists have found that a wildfire’s shape starts out the same
everywhere in the world.
Click here to see what the model shows about a fire’s shape and behavior.
(18.1 MB QuickTime movie. Click
here if you need to install the QuickTime viewer.)
What Does the Model Show?
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As you view the model running, you will see that the terrain is perfectly
flat. Watch the arrows at the bottom of the box. They represent the wind, which is blowing from the left
to right. |
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The fire suddenly ignites, perhaps due to a lightning strike or a careless
camper. The fire quickly takes on the shape of a triangle.
The hottest spot is its head, which is moving to the right into new fuel,
pushed forward by the wind. The fire’s sides or flanks are parallel to the
wind. At the fire’s back (at the far left), the flames creep slowly against
the wind. |
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The combustion of trees, shrubs, and grasses releases intense heat, which
quickly warms the atmosphere. The hot air rises, forming powerful updraft winds.
More air is drawn into the fire from all directions. On the fire’s
flanks, whirlwinds or fire devils move rapidly toward the fire’s head. |
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Suddenly, the fire leaps forward into new fuels and the fire’s path is
widened. The wildfire is changing weather that is already there! We call this
phenomenon wildfire weather. |
How Is the Model Useful?
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For many years, computer models have been helping
meteorologists to forecast the weather. But how can wildfire models be
useful? They can help us to
understand interesting and erratic fire behaviors, such as those
shown in these photographs. This is important, because we must balance
both the threat and the benefits of wildfires. |
| Smoke creates regional haze, air pollution, and the hazard of
smoke on highways. |
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Current land use practices are resulting in more people
building homes in areas at a high risk for devastating fires. |
| Intense fires destroy ground cover, resulting in soil
erosion and mudslides when it rains. |
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When plants burn, stored carbon is released as CO2, a
greenhouse gas implicated in global warming. |
| Global-climate events, such as El Nino and La Nina, can
cause droughts, making tinder-dry fuels a fire danger on several
continents. Here you have a satellite view of a fire in Vietnam.
The smoke plume is passing out over the Indian Ocean for hundreds
of miles. |
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Low snow accumulations here in the Rockies will reduce
stream run-off and moisture in forests.
This makes the summer fire season a very big worry to people living
all across the American West. |
| But wildfires are beneficial, too. They reduce fuel buildup,
and that helps prevent even bigger fires. |
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They improve the mix of plant species and enhance wildlife
habitat, and lead to forests that are filled with fewer but healthier
trees. Some plant species, like the aspen, depend on fire for
reproduction. |
| Wildfires are here to stay. Understanding them and creating
predictive models of how they interact with the atmosphere can help us to
live more safely with wildfires. At NCAR, we are developing ways to use
these models to plan prescribed burns
that reduce fuel buildups. Such careful planning can prevent flames from
escaping onto adjoining lands and smoke from drifting into populated
areas. |
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In the future, when raging wildfires must be controlled, models
may be used to
predict where a fire will go and when terrain, weather, and fuel
conditions can combine to produce dangerous fire behavior. |
| This would help fire crews position equipment on the ground
so that they can minimize damage and stay safe. |
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So that's why we're using computer models here at NCAR, to
help us understand wildfire weather, one of the most powerful and
important wonders of the natural world. |
Meet a Scientist
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Janice Coen is a scientist at the National Center for
Atmospheric Research. Dr. Coen’s current research involves studying and
trying to better understand explosive fires. She has authored a number of
publications on such topics as the effect of atmospheric winds and
windshear on fire behavior, and the effect of terrain on fire behavior.
Dr. Coen played a critical role in developing the first fire-atmosphere
coupled model.
Photo by Carlye Calvin
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