When fighting forest fires using pumper trucks and a convoy of water tankers you have to chew the soil with the force of the water from the hose nozzle as you move forward. The fire you thought you had put out can otherwise travel from tree to tree underground through the roots and also erupt from where a root reaches the surface. Failure to follow this procedure can result in the fire burning through your hose somewhere behind your team as the fire closes the path back out (losing the hose is extremely bad btw because it doesnt just bring you water, its your breadcrumb trail back through the smoke and the poles you use to climb up and down into rock crevasses to fight fires on the other side of a gap). The ashes are wet, the earth is wet, and small smoldering and still potentially dangerous embers lay all around and are still falling from from standing trunks. A re-eruption of flame if you erred or the fire re-spreading to standing fuel from an as not yet controlled part of the forest makes sleeping on the ground there nearly impossible as the ashes are part of the mud and extremely foolish due to falling drifting ignition sources.
I have never fought forest fires in coordination with aerial fire suppression teams though I suspect much of what I stated previously remains true.
...Oh ya, and there is a lot of steam from all the hot trunks and things youve sprayed, sometimes it can be thicker and harder to see through than the smoke. Imagine sleeping in a steam room with all your clothes on...