Evidently Colorado Division of Fire Prevention and Control's Multi-Mission Aircraft (MMA) "Guardian 328" (N328SF) is assisting with the search. If anyone knows what frequencies Guardian 328 might be using for this operation, please advise.
I don't want to say this is the correct answer but I believe Rocky Mountain conducts most of their own S&R missions. Depending on the complexity of the mission then other agencies will get involved. Rocky Mountain is within multiple counties so Rocky Mountain Rescue, Larimer County S&R, Grand County S&R could get involved. In some searches FFL, military, and other search organizations may get involved.