Wildland Fire Facts: There Must Be All Three

Each year more than 100,000 wildland fires occur in the United States. One is probably burning somewhere while you read this. There must be heat, fuel, and oxygen for a fire to exist. Remove one of the three elements and the fire will go out.

If your clothing catches on fire, be sure to stop, drop, and roll. Rolling on the ground smothers oxygen and the fire goes out.

Oxygen, Fuel, and Heat

Fire triangle diagram.

NPS

These three elements make up the fire triangle. Remove any one of them and the fire will not burn. Heat first comes from the ignition source that in nature is lightning or lava. Fuel is any material that will burn. Some fuels are more likely to burn than others. For instance, dead trees, leaves, needles and grasses have far less water in them than living ones. Dead plants usually burn sooner and hotter than live ones. If you have ever built a campfire you know this. At least 16 percent oxygen must be in the air for a fire to start. The air we breathe has 21 percent oxygen, more than enough to allow a fire to burn.

Oxygen

Firefighter puts water on flames at Olympic National Park.

Olympic Interagency Fire Management

Oxygen is all around us in the form of air and wind. A fire can be suffocated by removing the oxygen that feeds a fire. This can be done with water or dirt.

Fuels

The 10 Mile Fire burning at Olympic National Park.

NPS

Fuel can be live or dead trees, grass, dead material on the ground, and even wooden structures. A fire does not differentiate between these different types of fuel. Fuel can be removed from the path of a fire by digging fireline or even by carefully setting a fire that will consume fuel in the path of an oncoming fire.

Heat

Desert lightning storm over Big Bend National Park.

Jennette Jurado/NPS

Heat comes naturally from lightning or lava. Water from a fire engine or helicopter, as well as rain or snow, can remove heat and quell a fire.

Firefighting is Based on the Fire Triangle

Tactics and equipment are designed to remove heat, fuel, or oxygen. That even applies to you! If your clothing catches on fire, be sure to stop, drop, and roll. Rolling on the ground smothers oxygen and the fire goes out.