Been kind of obsessed with the fires here since LA’s basically surrounded. The sky’s been a dim rust color for a week and the morning sun shines with a yellowish tint like twilight. Its really messing with my internal clock!
Anyways, how are backfires done? Is anyone here a firefighter and has lit a backfire? I imagine its more than simply deciding on a spot and tossing a lit match into some brush. Is there some standard materials that are used? How big does it get before they put it out? I sort of have this crazy idea that you’d have a bunch of firefighters surrounding a small patch of fire (like a campfire) then turning on the hose before it gets too big. That can’t be how its really done, can it?
Also, when trying to put out a fire, do you aim the hose at the edge of the fire and push in or spray it directly into the heart of the inferno? And should you use a sweeping motion or direct it at one spot and douse that before moving on?
Backfires are usually controlled by clearing a border around it (a firebreak). Some firebreaks are permanently maintained and may double as dirt roads in the back country, but others are created for a particular controlled burn and then allowed to grow back.
Since the firebreak naturally stops the progression of the fire, the firefighters are mainly concerned with making sure there aren’t flying sparks or embers that could jump the break.
If you really want to know about wild land firefighting and the people who do it (and the women who love them), read Jumping Fire, by Murry A. Taylor. He was a smoke jumper in Alaska for many years.
The book is funny, sad and very informative.
Backfires can be set with flares (this is what the firefighters are mostly using in LA) as well as torches and even devices resembling flamethrowers. Certainly no books of matches or Bic lighters
While backfires can take advantage of existing firebreaks, they also take advantage of the fact that certain areas have already been burned, and thus will have no fuel should the fire double back towards that area. This is what has been happening in the Glendale/La Crescenta/Altadena areas-- they are burning some remaining vegetation between the homes and the current perimeter to exhaust that fuel close to the threatened structures.
As for water placement with the hose, it will vary depending on the fire and materials that are burning. Sometimes water is used to cool off adjacent stuff to keep it from reaching its flashpoint. Sometimes the flame source is completely doused-- this removes two of the three legs of the Fire Triangle-- heat and oxygen. Sometimes they will, as you asked, spray from side to side, but this generally does not do much more than create a great deal of steam and the direct focused attack will produce more tangible results. Generally the direct attack and the adjacent attack are the most common. Of course, there are many types of fires where water cannot be used as an extinguishing agent, primarily electrical and hazardous materials fires.
They set fires close to threatened structures? So… the “other” fire won’t come close and… threaten the structures… with fire?
Sorry, I just don’t get it. What’s the difference between letting the “wild” fire consume that fuel vs. letting an intentionally set fire do the same thing? Isn’t a fire a fire?
No. The winds are favorable (on shore flow-- blows away from the residences) and the humidity has increased. So you burn the fuel near the structures, so if the fire doubles back (again-- it’s changed direction about 8 times so far) it will run into a hillside of burned fuel, instead of a hillside of thick dry and unburned fuel.
Based on the latest news, it would be more accurate to say it “was started” near that station. Because it seems the authorities are now saying the fire was not caused by lightning, but was started by humans.
