Civilian agencies, like the NFS, are probably not going to be able to afford the multimillion cost of medium and large RPV systems. But, the military can. And, if you recall, the Navy and Marines were used in the 2014 fires in San Diego. A lesson learned from the administrative SNAFU that prevented them from being used during the 2007 San Diego fires.

If you also recall the Rebel Heart incident, the funds for the rescue came out of the Navy's training budget. Outside of what you do when you find the target, there's probably not a great deal of difference in finding lost adventurers in the western US, and hunting down insurgents in the Mid-East (look at the topographies: Mountains and desert). I can't imagine that the military would balk at being given the chance to use real world incidents (i.e. wilderness and disaster SAR) for training.

EDIT: Speaking of small RPVs for SAR...
http://www.nbcsandiego.com/news/local/Life-Saving-Drones-304946231.html