When I was in the oregon natl' guard in the summers of 2000 and 2001 we got activated to help fight forest fires. We got stuck on mop up wich is after the fire was put out we would walk the whole area with tools and water bags and check for hot spots. we spent 12 hr days climbing hills through knee deep ash looking for "smokers" or areas still burning. One thing I learned was somtimes the root sytems catch fire and smolder under underground. causing a person to fall hip deep into burning charcoal. The ground was so hot I melted the soles off two pairs of boots in two weeks.