A Standing Army of Lost-Person Searchers?

It seems that once or twice a year, there's someone lost or missing in a park or wilderness or canyon, and there's a general call for people to help with the search.

It seems that the runners and riders of the world could really help out here, and many have already. The issue is that a) there is no central place for such announcements to be made, i.e. there's no Bat Signal for long-distance search teams; and b) search-and-rescue does require specific knowledge and training.

If it doesn't already exist in the area (I'm relatively new to San Diego) it seems that there's an opportunity here for us to make our fitness and love of the outdoors more useful. Imagine if many or most of the runners and riders in the area had already volunteered for a few hours of basic search-and-rescue training on some Saturday in the past. The next time the Bat Signal goes up (text messages, RSS feeds, cascaded on Meetups and at athletic stores) then bang, the search authority has a few hundred new pairs of hands (and legs) that actually know what they're doing. Granted, emergencies don't always happen on the weekend and not everyone can drop what they're doing at 2pm on a Tuesday when there's a lost hiker or missing person - but some could, and that's better than nothing.

Does this already exist and I'm re-inventing the wheel? (If so, how do I get the training?) Or if not, does this sound like a useful idea?