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Comment by londons_explore | Hacker News Reader

In % of land area burned, the fires are pretty small. Far less than 1% of the US land area burned this year.

So, given the same weather conditions, you should expect more fires next year.

That isn’t the statistic I would expect to be pulled out here. Not all land area has any chance of catching/spreading a fire. Fires don’t really spread through rainforest; they definitely don’t spread through rocky areas; nor, really, through swampland; nor across mountain ranges; nor through irrigated cropland. (Nor through modern concrete cities, but city land-area is negligible.)

There’s definitely some portion of the US land mass that’s covered in either dry brush, dry underbrush, or dry grass. But that portion is pretty small, I would think. It could actually be that a fairly large portion of “potentially burnable” land-area catches fire each year. (That doesn’t imply anything about there being any less of it for next year, though; it recovers!)

I read it as less than 1% of all land that has burned this year. Not 1% of all land in the US. Can you imagine if 1% of the entire of the US burned!

There are 1.9 billion acres in the contiguous US, making 1% about 19 million acres.

a bad wildfire year is ~10 million acres or ~0.5% (https://fas.org/sgp/crs/misc/IF10244.pdf). It seems conceivable that we surpass that significantly this year.

Wow. Really puts it into perspective. That's equivalent to approx. the four smallest states all burned out.

This propublica story has a lot of detail on the fires. They estimate that there are ~20 million acres overdue for burn and the fires this year are burning about a million acres. If I understood it correctly a million acres burning a year is about what's required for stasis, but the 20 million acre backlog will need to be burned too.

https://www.propublica.org/article/they-know-how-to-prevent-...

At this point over 3 million acres [1] have burned in CA alone. So, seems like some of the 20 million acre backlog is getting burned through this year.

1: https://www.fire.ca.gov/daily-wildfire-report/

OK, so in three equivalent years, 50% of what needs to go will be gone - and that will give "herd immunity" to the unburned parts - 'till those get large again, say in 5 more years.

> Fires don’t really spread through rainforest

The region in question is one of the largest temperate rainforests in the world.

Also, when these fires burn mature forests, they don't actually burn the huge trees, just the smaller brush. However, they are so hot that they kill the huge, mature trees. So a couple of years later, you have a huge amount of dead trees ready to burn again.

Oh, I did not think nor knew about that one. I was more curious about does this have the same effect as controlled burning / prescribed burning but this seems to be making things even worse then. Thank you all for answers :)

Prescribed burning is usually done outside of the peak season (often in the later Autumn) just so it is more controllable and less intense.

It's amazing how fires can differ. Many "good" fires just essentially smolder for months, growing very slowly until the autumn precip douses them. The FS just lets them burn if they don't threaten any structures. I've even hiked directly over smoldering ground before, with no danger.

This description is painting with a wide brush across many different western tree species.

A douglasfir forest that burns is going to behave much differently than a late-successional hemlock one.

Why is that? Sap content? I just started reading Hoadley's "Understanding Wood" [0], which has gotten me interested in wood's characteristics.

[0] https://www.amazon.com/gp/product/1561583588/ref=ppx_yo_dt_b...

Some species are specifically adapted to either be able to survive frequent brush fires, and some even require them for seedlings.

Douglas-fir trees have very thick, insulative bark that prevents the live tissue from dying as readily when there's fire. Sequoia trees have cones that are glued shut by resins that only melt after a hot-enough fire, so they can then land and germinate in burnt-over ground.

https://en.wikipedia.org/wiki/Serotiny

https://en.wikipedia.org/wiki/Pyrophyte

Thanks for explaining! Trees are amazing.

And to connect the dots, the smaller brush will return every year. So there's really no meaningful limit here; it can be this bad or worse every year to come.

I'm not sure the US as a whole is the right comparison, since not all areas are equally prone to wildfires. Each of the West Coast states is above 1% of their land area burned, with California and Oregon pushing 3%.

Weren't these fires caused by a party?

There are hundreds of fires across thousands of miles. So no. Many were caused by dry lightning and other natural phenomena.

Thank you that makes sense

This is a perfect illustration of how news and social media propagate false news while technically still being correct. The gender reveal party contributed to 8,600 acres on fire. However, >1 million acres were started by lightning[0], but get a lot less coverage unless you're in the affected areas. But the party gets more attention, because it's more interesting/easier to be outraged over that.

0: https://en.wikipedia.org/wiki/2020_California_wildfires#List...

I'd be interested to see an analysis trying to track down the exact lightning bolt that started a fire. 100% of lightning bolts are now mapped by various open source websites to a precision of hundreds of yards. That, combined with lucky satellite shots a few hours afterwards should be enough to confirm the fire started in the same place as the lightning bolt.

Using that, it should be possible to identify what percentage of fires were in fact started by humans who were never identified (due to there being no lightning bolt within a few hours of the fire starting)

It's not hard to figure out that lightning is the the root cause for these fires. Lighting storms occurred only once this summer in California, and fires were noticed immediately the day after.

Unless there were a committed group of arsonists that wanted to use the lightning storm as a cover and worked to set fires on the same day that has a similar signature to lightning.

I don’t think it’s an outrage thing, but it’s an interesting anecdote on how some of the fires started. Lightning and campfires seem to be the usual cause, so something totally different is novel.

I find the fact that people should be outraged over this incident ancillary. Hopefully these people owe tens of millions in restitution, as often seems to be the case. But, if the fire had started because of escaped monkeys starting fires, I think it would be equally as reported on because of the novelty, but sans outrage.

The “it’s reported on because it outrages/divides people” speculation is just lazy.

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