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Wildfires: A Brief Explainer

Wildfires need three ingredients: heat, fuel, and oxygen.

Smoke and mountains in the background, a neighborhood in the foreground.

Photo: Robert Couse-Baker (Flickr)

An image of the Solano Wildfire.

There are two major wildfires currently in the news: The Eagle Creek wildfire in Oregon and Washington state and the La Tuna wildfire in California. The Eagle Creek wildfire was caused by people, while La Tuna was a naturally occurring brush fire.

Eagle Creek

Approximately eighty percent of wildfires in the United States are caused by people. Eagle Creek is thought to have become the much bigger fire it has become due to teenagers misusing fireworks on a nature trail. People in Oregon and Washington are reporting an “ash rain” falling throughout the states.

For a wildfire to form, there needs to be three ingredients: a heat source, fuel, and oxygen. It can be hard for people to remember that the nature surrounding them—brush, prairie grass, trees—are excellent fuel for fires, especially in the right weather conditions.

Weather For A Wildfire

Drought conditions where soil no longer holds moisture that can make it harder for a blaze to take hold make it much easier for a wildfire to start. It might also seem counterintuitive for some, but high winds can also help a fire to spread.

An excessive rainy season can also increase the potential for forest fires. Excessive rain and resulting blooms allow grass and other potential fire fuel grow in locations they don’t usually grow.

Winds

Wildfires aren’t a situation where a strong burst of wind, like when you blow out your candles on a birthday cake, will blow out the fire. Strong winds, such as the santa anas in California, give wildfires an oxygen supply. These winds can also keep the air dry and that can also keep the fires going for longer.

In some extreme conditions, a wildfire can produce a fire whirl. Fire whirls, which are also occasionally called fire tornadoes or fire devils among other terms, tend to only last a few minutes.

a fire whirl

From the photographer: “A still frame (one of 40,000!) of a 40 minute fire tornado event filmed by me at Mt. Conner in the remote outback of Australia on September 11 2012.” Photograph by Chris Tangey.

They are not formed in the same way tornadoes are, but are formed by hot air rising from the ground. As more and more hot air from the ground and from the surrounding fires gets pulled into the air, it rotates. Added into the mix are burning materials.

Not All Bad

While wildfires are devastating, they are sometimes part of an ecosystem’s necessary life cycle. These fires destroy disease that can have begun to plague the trees, burnt down brush allows the necessary light to reach usually shaded forest floors, thus allowing the plants that live there to thrive, and the fires also return nutrients from dead plants and decaying animals to the forest’s soil.

What To Do

The majority of the United States is vulnerable to wildfires. One easy way to protect yourself and your home is to pay attention to weather reports with fire advisories. Heed the recommendations, such as forgoing having a bonfire, and being careful about your use of flammable materials.

You can also check to see what your state or city recommends for fire hazard reduction. For example, some cities in California ask their residents to have their homes 200 feet away from brush. This distance gives firefighters a greater chance to save a home.

Ready.gov and the Red Cross urge people to keep an emergency preparedness kit in their homes, in case of a wildfire. Even if you don’t live in a place that regularly has fires like the Western United States, as climate change continues to bring high, dry heat to different areas, it’s in your best interest to be prepared.

Sources And Further Reading:

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