I've posted some of these before.
In 2019-2020 we had the 'black summer' bushfires in Australia.
Pic taken from my house. The fire reached me about two days later and came within a few hundred metres of my property.
A couple of weeks later I bushwhacked my way back into the rainforest that got burnt. It was still smouldering.
The soil was burning under the surface.
And spot fires were still breaking out.
I wanted to put the fire out, to stop it from reigniting the next time there was a hot windy day. The only way to do it was to cut the burning soil out and stomp on it until it was out.
Bushwacker Mistress cutting out soil, block by block.
I cut out a few areas like this, probably ten square metres of soil in total. You can see the smoke still hovering in this hole.
Washed the knife off in a stream afterwards. When I got home it still cut paper.