I asked a firefighter when is the fire considered safe once it appears to have stopped burning? The answer surprised me a bit. You need to have a 100m strip around the fire where someone has raked or inspected inside every tree, under every cow pat, bit of grass to make sure nothing is smouldering in that area. This is a huge job as for the fire I enquired about (Cudlee Creek SA), the perimeter is 180km and a fair bit of this is in rugged terrain. So a ton of work.
Honestly I'm surprised that's sufficient. To my knowledge you can even have root fires burning underground for months. And I expect embers can travel in the wind far longer distances than 100m. It's pretty impressive to me they can do it with 100m of inspection, let alone how difficult that already is.
> And I expect embers can travel in the wind far longer distances than 100m.
Far, far more. Embers have been known to travel 10s of km. However, if that happens after a fire has been reduced to smouldering, if it lights something, that gets considered as a new fire.
