Anything for you @daveregrets. So the first thing is that wildfires don’t get put out by people with hoses. They are contained and then the winter puts them out (usually). So what firefighters are trying to do is draw a line in the earth around the fire that it cannot cross. https://twitter.com/daveregrets/status/1297744585536335872

How does that happen? The main thing that wildland firefighters have to do is to construct fire line. Fire line is just a stretch of mineral soil that can’t burn and is wide enough that flames cannot cross. Sometimes a road will do. Usually it has to be built from scratch.

This is brutal hard work. Brutal. Lots of chainsaws, bull dozers, and of course, Pulaski’s. All off trail in heat and smoke. Firefighters also use backfires (they call them firing operations) to burn fuel between a containment line and the oncoming fire.

https://en.m.wikipedia.org/wiki/Pulaski_(tool)

So % containment is the percentage of the total fire perimeter around which firefighters have been able to construct line they think the fire won’t cross.

But sometimes of course, the fire grows bigger in an uncontained section so containment can drop. And sometimes containment lines do not hold despite firefighters best efforts. Containment falls that way too. Thunderstorms like tonight can wreak havoc. Fingers crossed.

Last thing to remember: in a wildfire the safest place to be is in the black - if you are ever in a place with a lot of fire, what you want to do is find your way into one of the already burned patches. That is a place of safety because fires need fuel.

Once all these fires are contained, then they will still burn until the rainy season. So smoke impacts and also lots of VOCs (ozone precursors) will continue to be emitted. But houses won’t burn down.

Last last thing - firefighting itself can be damaging to land. So there’s a bunch of post-burn rehab that will happen to try to stabilize slopes. That’s called burned area emergency response (BAER).

Got questions? I’ll try to answer them. Also, there’s a bunch of people that follow me who have spent decades fighting wildfire. I’m sure they will set us straight if I get something wrong.

@polarscribe points out I never mentioned all those planes and helicopters. Duh! Their role is not to put out the fire or to construct line. It is to slow down the fire so that firefighters can construct line and get containment. They work best when you can hit a fire early.