Mark,
When Boone County dispatches fire and ems, they send the dispatch on the dispatch channel, and at the end they say "Ems Ops" or for fire, "Fireground 1." This assigns the responders to a specific channel so as not to tie up the net. Then let's say they get ANOTHER fire or medical call during the initial one, they will assign the next crew to "Ops 2" or "fireground 2."
Just a means of organizing the fire and ems crews.