Wildfire Corner: Is your Burn Pile Out? Really Out?

Small burn pile.
Small burn pile. Photo courtesy of CalFire.

Did you do some outdoor burning this winter and spring? If so, please read on because outdoor burning is the leading cause of wildfire in northeast Washington state.

You may be wondering, how does a burn pile become a wildfire? One of the leading reasons is “failure to extinguish” the pile.

Did you know that a pile burned in January can start a wildfire in July? People are often surprised that a pile they burned during the winter and then saw covered by three feet of snow, followed by four inches of rain and produced no visible smoke for six months can still start a fire in summer. It is true and this is how it happens:

The conscientious landowner burns the pile when fire danger is low and outdoor burning is allowed. The pile burns down but some of the material may be mixed in the dirt beneath the ash. Due to the scarcity of oxygen at the bottom of the pile, this material may continue to burn but very, very slowly. It can burn so slowly that no smoke is seen, and the heat produced is so minute that it does not melt any snow that falls on the top of the pile. When you feel the top of the ground with the back of your hand you’ll likely feel only cold ash. But, when summer arrives and the weather warms up, a piece of that slow burning wood near an outer edge of the pile may become exposed to air. The result could be a small flame. If that flame touches nearby dry grass or other dry vegetation, you have the next wildfire.

I have worked on numerous wildfires over the years that started from a pile that the landowner said was “out” and was sure had been out for months. Many times I have walked up a burn pile that looks like it is completely out. I may see no smoke and feel no heat when I touch the ground, but when I put my shovel into the pile and dig into the ash I might find burning material six inches, or maybe even a foot, below the pile’s surface.

What can you do to help ensure your burn pile is fully extinguished?

Use a shovel to dig down into the pile. Dig in several spots in each pile you burned.

Feel the ash with the back of your hand (not your palm). We use the back of our hand because it is more sensitive to heat and, of course, we do not want to get a painful burn on our fingers or palms. If the ash you’ve uncovered feels warm at all, dig deeper to find out where the heat is coming from.

Remember a fire is out only after you dig into it with a shovel and feel no heat in what you dig up. Always dig completely through the ash layer into the dirt below to be sure you’ve haven’t missed anything.

By Guy Gifford, landowner assistance forester & fire prevention and Firewise coordinator, Washington State Department of Natural Resources, Northeast Region, guy.gifford@dnr.wa.gov