I got to thermal over a controlled burn near Hernandez once.
It was a very small one but provided good thermals and
easy to follow by smelling the smoke. I reported
it on flight following and FSS, and got back
that it was controlled.

During some of the more recent fires I got to fly over them
at night. The firefighting restricted areas were only to
6000MSL, and flying over at 6500 at night was really
stunning to see. Fortunately these were fires in
Northern Calif. two months ago that took no lives or property.