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Words of the Day - Learning the Language of Fire
This page is meant to provide some of the key fire terms we use when addressing wildfire.
Mop-Up
What is ‘mop-up’? Do firefighters own a bunch of mops? Will it help me get home faster? If you’ve asked these questions you’re not alone.
If you’re scratching your head trying to imagine firefighters working with a bunch of commercial style mops and dirty water buckets out there in the countryside, we’d be right there scratching our heads too. Rest assured, we’re not fighting this fire with mops, or buckets of soapy water.
For our wildland firefighters, mopping-up describes the hard physical labor process of extinguishing or removing burning material near control lines down to the mineral soil, felling fire damaged trees, and cooling ash pits to make a fireline less likely to escape or to reduce residual smoke. This is followed up by ‘cold-trailing’ with the back of one’s hand along the ground near the fireline to make sure no heat remains.
On a typical fire crews will ‘mop-up’ to the extent necessary to minimize the likelihood of the fire moving into unburned areas outside of the edge of the fireline. That’s right- no burning stumps, no smoldering ash pits, no heat for a safe distance into the black area of the fire perimeter.
Fuels
You can't have a fire without fuel. Fuel feeds a fire by providing energy, and can be anything from live or dead plant materials to structures, like homes. Fuel is the only component of the fire behavior triangle that land owners and managers can influence.
Fire behavior is dependent on certain fuel characteristics - type, amount (loading), availability, and arrangement.
There's a variety of fuel types out in the forest:
- Ground fuels include organic matter such as peat, duff, and decomposing roots.
- Surface fuels are fuels on the ground such as needles, grasses, moss, lichens, forbs,shrubs, twigs, branches, tree trunks, and other herbaceous material.
- Ladder fuels convey flames from the surface level up into the crown. Examples ofladder fuels are tall shrubs, small and medium-trees, and low-hanging limbs.
- Crown fuels are foliage and small branches of the forest canopy.
All of these factors come into play when fire teams approach addressing a fire.
Intensity
For today's "Word of the Day" let's talk about fire "Intensity." As a general rule of thumb, we can say that fire is hot. Just like we can say ice is cold. But, how hot is fire? The heat created by a flame from a Bunsen burner, for example, is much greater than the heat created by a candle flame. The same is true with forest fires. Some fires give off much more heat than others. That is, they are more intense.
Fire intensity is simply the amount of energy or heat given off by a forest fire at a specific point in time. A lot of factors influence fire intensity, such as weather conditions; amount, size, and moisture content of the fuel (i.e., fuel load); plant chemistry (e.g., conifer needles that emit flammable terpenes contribute more to fire intensity than green maple leaves); and topography. It is very rare to have a fire burning with wall-to-wall flame that burns everything in its path. Much more commonly, fires burn in what we call a matrix of intensities with some total loss of trees but areas that might be seemingly untouched. That means that within the fire perimeter you see on maps now in the Northwest, there will be areas of high and low intensity fire activity.
Containment
What is ‘containment’? Why has containment remained at zero percent? Does containment equal success? If you’ve asked these questions you’re not alone. Our intent is to help folks understand what’s what and increase your understanding of what these terms mean out on the ground.
‘Fireline’ is the hand or dozer line that firefighters put in down to bare mineral soil to hold the fire and keep it from growing. Over the past several days, crews have worked tirelessly to put in hand-cut and dozer lines to help protect communities.
Combined with favorable weather, these lines have been successful at limiting new fire growth towards populated areas.
But fireline by itself doesn’t equal containment. We only call a section of line ‘contained’ if there are no more ‘hotspots’ or heat near the fireline. We’re not going to call an area of line contained if there is any chance it could ‘come back to life’ and allow the fire to grow past the constructed line. In fact, crews monitor all constructed fireline areas for several days- putting out burning stumps, cooling ash-pits, and walking the ground over and over to ‘cold trail’ by hand. Your life and safety is our number one concern.
Every day, every fire, every time.
Burn-Out
What is a ‘burn-out’? Does this mean you’ll be putting more fire on the ground? How would that help? If you’ve asked these questions you’re not alone. Our intent with this special update is to help folks understand what’s what and increase your understanding of what this means out on the ground.
A firefighter’s style of ‘burn-out’ has nothing to do with tires, racecars, or cheering fans. In the world of wildland firefighting, a burn-out is defined as intentionally putting fire inside a control line to consume fuel (brush, logs, grass) between the edge of the fire and the control line to create a buffer of burned area around the edge of the fire to help secure the area. This strategy ‘starves’ the fire of fuel and allows our hardworking engines and crews to engage the fire on their terms.
Burn-outs will help limit the fire’s spread towards communities. So while you may see more fire or smoke, it’s our hard working crews doing their best to keep you safe today, tomorrow, and for the future.
Click here to learn more.
Cold Trailing
A method of controlling a partly dead fire’s edge by carefully inspecting & feeling w/the hand for heat to detect any fire, digging out every live spot & trenching any live edge.
Wildland Urban Interface (WUI)
The WUI) is the area where human development and the natural world meet or intermingle.
WUI communities can utilize resources such as community wildfire protection plans (CWPPs) and the Firewise Program to reduce their risk of losing life and/or property from wildfire. CWPPs allow
communities to proactively manage their wildfire risk through working with local emergency management and land management agencies by mapping values at risk and by reducing fuels.
The Firewise Program provides tips for reducing wildfire risk based on the landscape’s proximity to the home, also known as the areas of the Home Ignition Zone. Typically, closer to the home, effort should be made to maintain your landscape with well irrigated lawns and fire resistant plantings, while further out homeowners are advised to prune and selectively thin native species.
If you are not sure whether you live in a WUI area, contact your local fire department or land management agency. They can help make a determination based on the specific conditions around your home. Living in fire prone areas comes with great responsibility. Be proactive at reducing your wildfire risk while living in the wildland urban interface.
Contained, Controlled & Out
For our fire "Word of the Day," today, we're going to distinguish between a few terms we've been hearing a lot lately: contained, controlled & out. A fire is contained when the fire is encircled by constructed fire lines or other fuel breaks such as roads, streams, etc., and there is a reasonable expectation that the fire will no longer spread beyond these lines. When a fire is contained, there may still be active flames that threaten to cross the lines. When a fire is burning it is common for reports to come out stating that a fire is X% contained. For example, a fire that is 20% contained means that some combination of fire lines and other fuel breaks surround 20% of the perimeter of the fire.
A fire is controlled when it is fully contained, and crews have extinguished flames and smoking/smoldering fuels, and removed unburnt fuels from about 300 feet inside the fire line perimeter. This effort may take several days once a fire is fully contained. Any hotspots that are immediate threats to these lines have cooled down enough so there is little chance that flames will cross the fire boundary.
A fire is considered to be out when no hotspots and smoke is detected within the lines for at least 48 hours. However, large wildland fires are often watched and patrolled until rain or snow eliminates all smoke.