Top 5 Ways That Wildfires Start

Woolsey Fire
A house burns during the Woolsey Fire on Nov. 9, 2018, in Malibu, California. Residents of Thousand Oaks are threatened by the ignition of two nearby dangerous wildfires, including the Woolsey Fire, which has reached the Pacific Coast at Malibu. David McNew/Getty Images

Plenty of natural phenomena can turn the landscape into a blazing inferno and send wildlife racing for safety. Lightning, volcanoes, dragons -- all are devastating forces of fiery destruction that can start a conflagration in seconds. But despite how destructive it sounds, fire isn't always bad for a forest. In some ways it destroys, but it can also revitalize, clearing away cluttered brush and leaving fertilized soil and fresh growing space in its wake. In fact, some ecosystems depend on a regular fire regime to spur processes such as reproduction and germination.

Humans have long recognized the rejuvenating power of fire. Systematic burning gave greater access to food, for example, opening land for foraging and cultivation. And although the practice is less common today, many prescribed fires (also known as controlled burns) are set each year to coax swathes of land back to a fully functioning state.


But while fire can be fundamental for promoting healthy forest growth, sometimes too much of it is a bad thing -- especially when a blaze swells out of control and threatens homes and other important infrastructure. That's where the concept of a wildfire enters the scene. The National Wildfire Coordinating Group defines a wildfire as an "unplanned, unwanted wildland fire" including:

  • Unauthorized human-caused wildland fires
  • Escaped naturally caused wildland fires
  • Escaped prescribed wildland fires
  • Other wildland fires that need to be put out

Sometimes human-caused wildfires are set intentionally as an act of arson. It's often tricky for authorities to determine whether arson has actually been committed, but you can find out about some of their methods in How do investigators determine if a wildfire was caused by arson?

However, in this article, we'll be focusing on five fiery mistakes that can have catastrophic ecological and economic consequences if the flames burst out of control. Continue reading so you can find out how to avoid them and make Smokey Bear proud the next time you head off into the hills.

5: Burning Debris

Blazing yard waste can get out of hand in a hurry, especially if conditions are particularly hot, dry and windy.

Lots of people burn yard debris such as cut branches and cleared shrubs, but while this is usually legal with a permit, it can also be a dangerous practice under certain circumstances.

Weather conditions play a big part in whether it's safe to burn debris or whether your backyard burn could spell a wildfire in the works. For example, wind can quickly cause the flames rising off a pile of burning yard waste to spread into unwanted territory.


To prevent an accidental gust from generating a full-fledged wildfire, there are a few steps you can take to help ensure everything proceeds smoothly. For starters, give the fire department a call the day you plan to burn to get a professional opinion. They may advise you to wait a few days, especially if it's been particularly hot and dry.

Next, determine whether there are any potential hazards either hanging over your intended burn site or located too closely to the perimeter. Make sure there's open space at least three times the height of the debris pile above, and at least 10 feet (3 meters) away horizontally in all directions. That space should be watered down and covered in either gravel or dirt.

After the debris pile burns completely -- all under the watchful eye of an observer armed with a precautionary water supply -- it should be shoveled over and watered repeatedly. Then the site should be checked several times for the next few days and even weeks to make sure all the sparks are fully extinguished.

4: Equipment Issues and Unruly Engine Sparks

Without proper care and maintenance, mechanical devices can spell trouble for a forest.

The invention and eventual mass-production of the internal combustion engine and other now commonplace machinery might have helped modernize society, but they also introduced a new threat to the world's wildernesses. That's because without the proper precautions, a running engine can spew hot sparks and bits of burning debris -- a potentially dangerous situation if that device is operating in a field or forest.

Enter the spark arrestor. It's typically a small device, but it has a big role in protecting against accidental wildfires. Different types are tailored to work best under different circumstances, but all spark arrestors basically act like filters that let exhaust out and keep embers in.


Spark arrestors are also installed in woodburning stoves and fireplaces to keep potential igniters from escaping -- both inside and out. They're not a 100 percent guarantee against wildfires, but they definitely help increase the odds that a stray spark won't start a blaze.

3: Lit Cigarettes

Hey lady -- don't just drop that cigarette when you're through. It could cause big problems for your forest buddies.

Cigarettes are another common cause of wildfires. Makes sense -- they're certainly burning and they're easy to flick out of sight when a smoke break is over. But the careless toss of a still-burning cigarette butt can have serious consequences if it catches a forest on fire.

When out in the woods, smokers need to take special care their habits don't land them in a lot of trouble. Cigarettes, cigars and even pipe tobacco all need to be thoroughly ground out in the dirt until you're absolutely certain they're extinguished. A stump or a log is not a suitable alternative to an ashtray, and it goes without saying that leaves and other brush should be avoided. Also, even though it might seem gross to keep an ashtray in the car, it's far worse to simply toss a cigarette out an open car window.


2: Unsupervised Activities

With professional handling, fireworks are plenty safe. But in the hands of amateurs, well that's another story.

It might not seem like a big deal to leave kids to their own devices while parents work nearby pitching the tent or rooting around in the trunk for sleeping bags, but if the little ones get their hands on lighters or matches, that can change everything. Children aren't widely renowned for their capacity to decide whether something is a really good idea or an extremely bad one. Bottom line -- keep a close watch on anything that can start a fire.

On a similar note, fireworks should always be avoided when there's the chance they could start a wildfire. Sure, they're fun to shoot off, but as soon as they get going -- especially the ones that shoot into the air -- it's often completely impossible to control the outcome should things start to heat up.


1: Unattended Campfires

The campfire smell that clings to clothes can be a delicious  aroma. But if that same campfire causes a wildfire -- it probably just ends up smelling like shame.

Last, but by no means least, are campfires. Wonderful givers of warmth, light, s'mores and lots more, campfires can also cause wildfires if proper care isn't taken to keep them under control.

Just like with a debris fire, it's important to find a safe location for a campfire that's distanced from nearby ignitable objects and protected from sudden gusts of wind. Campfires should always be built in rock-ringed fire pits that are stocked with a bucket of water and a shovel.


And while it might feel satisfying to establish a roaring bonfire, that's a bad idea; campfires should be kept small and manageable at all times. On a similar note, when it's time to tuck in, the fire must be extinguished completely -- and that includes pouring lots of water on all the ashes and embers until the hissing and steaming fully stops, then using the shovel to stir everything around and separate out any bits that are not burnt. Keep it up until you're absolutely certain every last little spark is out.

To learn more about wildfires, forests and the truth about the much-maligned Mrs. O'Leary and her long-beleaguered bovine, hit up the links on the next page.

Lots More Information

Related HowStuffWorks Articles

More Great Links

  • "Fireworks Illegal on all Public Lands in Idaho." U.S. Department of the Interior Bureau of Land Management. June 29, 2009. (1/21/2010)
  • "Fireworks Restrictions in Place." U.S. Forest Service. June 27, 2002. (1/21/2010)
  • Pollick, Michael. "What is a Spark Arrestor?" WiseGeek. (1/21/2010)
  • "NWCG Communicator's Guide for Wildland Fire Management." National Wildfire Coordinating Group. (1/21/2010)
  • "Wild & Forest Fire." NOAA Economics. (1/21/2010)
  • Web site. (1/29/20)10
  • "Wildland Fire -- An American Legacy." U.S. Department of Agriculture Forest Service. Summer 2000. (1/21/2010)