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How do you fight a wildfire?
Photo by Leanne Clement
Fighting a wildfire is not like fighting a house fire.
When a house is on fire, the goal is to put the fire out as quickly as possible. This is mostly accomplished by pouring water on the flames, depriving it of oxygen and reducing the temperature of combustibles.
When a forest is on fire, the goal is to contain it, and allow it to burn itself out. This is done by removing fuel from a path all around the fire, known as the “containment line.”
The two types of firefighting thus attack different components of the so-called “fire triangle”:
The containment line is built piecemeal from individual stretches of “firelines” that gradually connect up to form a fuel-free perimeter around the fire.
Firelines are created in a variety of ways. “Hand lines” are created by specially trained crews that physically remove wide paths of flammable materials, stripping the surface down to bare dirt. Other firelines may be created by dropping long swathes of flame retardant by aircraft. Backfires may be set between the actual fire and the fireline to preemptively burn any fuel in that area in a controlled manner.
Once a fireline has been established, less trained personnel are needed to “hold it,” preventing the fire from breaking through. They will monitor fire activity, and put out any spot fires that may start from embers crossing the line. Aerial crews may drop water on flames to help prevent the fire from spreading in selected directions.
Deciding where to place firelines, and where to establish the containment line, is a very difficult task that requires predicting where the fire will go. Fire behavior depends on a number of factors, including the type of fuel available, how wet the fuel is, how hot it is, what the wind is doing, and the slope of the terrain.
On top of which, a large wildfire can create its own weather patterns.
Crew safety must be considered at all times, ensuring that personnel working on the ground have escape routes should the fire change direction or pick up speed. A wildfire can move up to 7 mph in wooded areas and up to 14 mph on grasslands without getting tired!
Needless to say, fireline placement takes advantage of natural fuel breaks such as roads, streams, and ridges. Artificial fuel breaks may have been created well before a fire starts as part of fire mitigation measures.
Finally, when the fire is contained, mop up crews put out residual fires along the fire perimeter to ensure that the fire doesn’t blow up again outside the containment area, even during high wind events.
So, fighting a wildfire is not like fighting a house fire. Except, of course, when the wildfire threatens homes and other structures.
Then firefighters have to switch from containment to suppression tactics.
Watch this video for more detail on wildfire firefighting.
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Don’t drone near a wildfire
Drones can be a valuable tool for gathering information and learning about what’s going on in a disaster area. They can also make matters worse.
When it comes to fighting wildfires, aircraft are used to drop fire retardant and water, monitor fire conditions, and provide tactical information to firefighters. Unauthorized drone flights near a wildfire pose a danger of collision with firefighting aircraft. According to the National Interagency Fire Center, drone “incursions” stopped aerial firefighting efforts 17 times in 2021 (as of Oct 18), and 41 times in 2016:
This not only puts lives at risk, but is a federal crime. Per the U.S. Code of Federal Regulations, 43 CFR § 9212.1, it is “prohibited on public lands to … (f) Resist or interfere with the efforts of firefighter(s) to extinguish a fire.” It may also violate FAA regulations, as the airspace over a wildfire is often subject to temporary closure.
Read this article for more on the challenges of unauthorized drones in disaster areas. Learn more about flying drones near wildfires here.
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Change the odds, save your house
Screenshot of homes–some burned, some not–in https://www.youtube.com/watch?v=STTZX2Gt_Pw
Why do some homes burn and some don’t, when wildfires burn through inhabited neighborhoods?
In this 10-minute video, Glass Fire Post Fire Analysis – For Residents, a fire chief leads an educational tour through a neighborhood that was ravaged by the Glass Fire of 2020. He shows houses — literally next to each other — one burned, one not, and discusses why.
“I really believe that if people had done their home hardening, and Zone 0 defensible space work, those homes would have survived. If they didn’t have flammable material within the 3-5 feet of space, if they blocked their eaves, or they had improved vents so fire could not get in their attic. I firmly believe they would have survived this fire.”
The takeaway: We cannot control a wildfire coming our way, but we can reduce the odds that our homes will burn.
Here are some highlights from the video:
- Protect your attic! Embers getting into the attics is the major culprit. “From what I see, every one of them burned from the attic down.”
- Consider your Zone 0 defensible space (0-5 feet from the structure). The video shows a scorched house literally next to an untouched house. The scorched house had flammable wood chips around it, the untouched had non-flammable cedar chips.
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“My God, it’s so simple!”
Photo by Tengyart on Unsplash
“My God, it’s so simple, … to prepare for this. It’s basically being sure your roof and your gutters are clear. And that you’ve raked … a walkway, … around the house that doesn’t have combustible material. … because they [the fire department] explained that what happens is embers fall and you don’t want them to be able to fall into duff. So you clear the duff.”
(Barbara Sprenger, in conversation with Susanne and Garett, Sept 2021).
Preparing your house for wildfire is called, “house hardening.” Many people are intimidated by this term, feeling that there is much to do and doing it is difficult.
However, as Barbara says, it really isn’t that hard. Basically, you want to ensure that a few embers won’t light your house on fire.
As Barbara says,
- Keep roof and gutters clear so embers won’t catch
- Keep combustible materials away from the house, so fire cannot “walk” up to your home.
- Cover attic vents with metal mesh, so embers cannot get inside.
CalFire’s ReadyForWildfire site has a large set of measures to harden (prepare) your home to help increase its likelihood of survival when wildfire strikes: https://www.readyforwildfire.org/prepare-for-wildfire/get-ready/hardening-your-home/
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Don’t inhale!
Photo by Susanne Jul
A few months ago, we were swimming in smoke.
Well, not me. I stop outdoor exercise when wildfire smoke pushes the Air Quality Index (AQI) above 125. Even though that’s below the 150 “Unhealthy” rating.
You see, AQI only measures five major pollutants: Ground-level ozone, particulate matter (including PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide. It doesn’t take into account all the other nasties that wildfire puts into the air, such as lead, zinc, calcium, iron and manganese.
Think, “Oh, yummm, I love that smell of burning wood. Especially when it’s mixed with burning cars, creosote/arsenic/penta-treated utility poles, and lots of plastic toys!”
A proper mask will filter out particulate matter. Which is the biggest threat to your health. But it won’t do anything about the nasty toxic gases. And it has to fit tightly — no cheating air sneaking in around the edges. And it has to be N95-grade (or “NIOSH-approved N95 Particulate Filtering Facepiece Respirator”) — a cowboy bandanna or triple-layer cotton COVID mask helps but won’t do it.
Read about wildfire smoke and public health in The Wildfire Smoke Guide for Public Health Officials.