How Do Wildfires, Forest Fires & Brush Fires Differ?

5 Mins read

There’s no shortage of wildfires in the news. The 2019-2020 fire season in Australia has been devastating. People around the world have responded with donations and support for people and animals. The season for wildfires depends on the weather conditions where you live. Over the past few decades, researchers have found that fire seasons are longer than they used to be, largely due to climate change. This is one reason that some areas need to be on alert all year long, rather than just a few months of the year. While fire retardants are a critical component to remain safe during an approaching wildfire, understanding the difference between a wildfire, forest fire, and brush fire can help you take the right precautions for your home.

What is Wildfire?

Wildfire is a fire that burns uncontrollably, usually in a rural area with a lot of vegetation. Although some wildfires occur naturally or by a force of nature, such as a lightning strike, most wildfires are started by humans. It’s estimated that 98% of wildfires are started by humans. A wildfire needs three things to start:

  • Fuel source: such as trees, grass, shrubs or bushes.
  • Ignition source: a way that the fire starts, cigarette, campfire, lightning strike, or fireworks.
  • Air: every fire needs oxygen to burn. High winds, like the Santa Ana winds in California fuel fires and cause them to spread.

When the conditions are right, these three elements can come together and cause a fire that can burn for days, even weeks. These fires can thrive in places that are hot and dry, which is what we’ve seen in Australia and California. Wildfires burn according to what type of vegetation is involved.

  • Ground fires burn organic material in the soil.
  • Surface fires burn materials on the ground, dry leaves, twigs and bushes.
  • Crown fires burn at the top of trees, jumping from tree to tree.

Although crown fires seem to burn with the most intensity, every type of fire can be quite deadly and hot. A wildfire in a forest can move at around 6.7 mph, destroying everything and anyone in its path. In Australia, there is concern about some species becoming extinct from the wildfires that have ravaged the country. Animals either try to relocate during a fire, or they try to find a safe place to hunker down.

Many communities evacuate when fire danger is imminent. If you do get trapped in a car or home, it’s recommended to close the windows and doors, but don’t lock them. Stay inside and cover yourself with a wool blanket. If you’re in nature and get trapped, get to an area without much vegetation. Try to find level ground or a ditch. Lie down and cover your body. In any situation, call 911.

Many of the largest wildfires in the history of the United States began from smaller fires that merged into one. The Great Michigan Fire of 1871 burned over 2.5 million acres. Coincidentally, it was on the same day as the Great Chicago Fire. The Michigan fire began from many smaller fires designed to burn off the debris left behind from the logging industry. The Peshtigo Fire in Wisconsin, also on the same day as the Great Chicago Fire, burned over 1.2 million acres with an estimated 1,500 to 2,500 deaths. It’s considered the deadliest fire in U.S. history and mostly forgotten because of the Chicago fire. The Peshtigo fire also started from many smaller fires that were fueled by the high winds off the lake and the dry conditions.

What is Forest Fire?

A forest fire is a type of wildfire that occurs in a wooded area. Some of the biggest fires in the history of the United States have been forest fires. The Great Fire of 1910 burned over 3,000,000 acres. The fire was mostly in Idaho and Montana, but British Columbia, Canada, and Washington state were also affected. It was this fire that raised public awareness of the importance of firefighters and the need for wildfire prevention.

Forest fires are sometimes set on purpose. This is called a prescribed fire or controlled burn. These fires are designed to help the forest maintain its ecological health. Prescribed fires are planned during periods when the fire won’t pose a threat to people and when weather conditions are right. The fire needs to burn dead grass and trees and the undergrowth of the forest. This does many things. First, it prevents wildfires from getting out of control if one does start. Second, the prescribed fire reduces invasive plants. The fire can also rejuvenate the forest by opening space for new plants and allowing sunlight to reach the forest floor.

Unfortunately, prescribed fires do get out of control. The 2000 Cerro Grande Fire in New Mexico began as a planned burn. It was part of a plan to reduce fire hazards at the Bandelier National Monument. High winds and drought conditions caused the fire to get out of control. Over 150,000 acres burned, and 400 Los Alamos families lost their homes. Total damages were around $1 billion. The fire burned for over a month before it was declared contained, and it took another six weeks before it was extinguished.

What is a Brush Fire?

A brush fire is one that starts in a prairie or scrubland. Many brush fires turn into wildfires if they aren’t contained quickly. In July 2019, a brush fire began on the island of Maui. Although there were no injuries or significant property damage, over 3,000 acres were damaged. Hundreds of people were forced to evacuate. The Camp Fire, considered California’s most destructive wildfire to date, started as a brush fire. Over 18,000 structures were destroyed. There were 85 confirmed deaths with 2 missing and 17 injured. Because the fire moved so fast through the brush and grass, there wasn’t time to evacuate the homes. It was a travesty.

Grass fires can travel very quickly, up to 25 km per hour (almost 16 mph). Don’t think that you can outrun a grass fire. You’d need to run a 4-minute mile to outpace this fire. Brush and grass can burn very quickly and spread very fast. Although grass fires tend to be less intense than forest fires, they are still dangerous. The fires can get extremely hot.

What To Do If You’re in a Fire

Wildfires, forest fires, and brush fires are very dangerous. If you’re in an area that is prone to fires, know where to find fire information for your area. If emergency personnel tell you to evacuate, leave your home immediately. Be prepared to evacuate during the fire season. Know the procedures for your community. Have a plan in place if a wildfire approaches your home.

If you are in a community where wildfires are common, before the wildfire, create a defensible space around your home. Clean up flammable vegetation to a minimum of 30 feet around your home. Keep trees and shrubs trimmed and away from chimneys and electrical wires. Use fire-resistant materials if you need to renovate. Design your landscape to make it easier for firefighters to protect your home.

Wildfires are a serious business. Every community near open prairies or forests is at risk for fire damage. Always be careful with fire. Most wildfires can be prevented.