It must be pretty dry there to have a fire burning down like that. And/or coupled with a bit organic (like peat) layer.... Need a real good soaking rain for a few days.
Duff fires are a bear to extinguish. That layer could be much deeper than you'd ever expect, have pits and low spots in terrain you'd never notice from the surface. If they cut a perimeter down to dirt, that thing will still smoke for a long time inside, unless they do a "surround and drown" approach.
For sure those are bad. I not so fondly remember a fire near Seney in MI's UP. Burned a huge area and fighters were brought in from all over they country. They thought they had the fire contained then 2 weeks later another one started. They found it burned underground and actually went under the highway then started up on the other side again. Wow.
It seems we've been in this dry spell for a good 45-60 days, even when we get enough rain to burn pine splits in the outdoor fireplace, it takes about three hours and the area behind the fireplace drys out. This is the first year that I've dumped about six gallons of water behind the fireplace when I'm done and another four inside the fireplace after burning.
The did dig a perimeter but I'm not sure on the surround and drown. Our town wood dumps is getting pretty full which is a good sign, more people bringing it there instead of burning it. I think it was over a year ago when our town hired a company to chip everything at the wood dump, I think that company uses or sells it for mulch.
