Everybody should be cognizant of the different types of military helicopters which have their own specialized missions. Seeing them in numbers or at certain times can help you figure out what's happening and to whom.
Reposting my earlier comment on configuration: The type of chopper could be significant. Do you remember if they had two very large rotors above a "mast" front and rear? That would be a cargo bird like a CH-47. These can haul one or two HumVees or a platoon of (40 or so) troops. It is somewhat ungainly and elongated. It sort of reminds one of a grasshopper. BUT a chopper with ONE HUGE overhead rotor and a smaller rotor perpendicular off a tail boom might be a "Pave Low" and those are used by Special Operations guys. Did you notice colors or camoflage patterns? Things for everybody to watch for in the future.
In the link, the drawing is the CH-47 and the photos are the Pave Low SpecOps bird.
Bump and thanks for I sure have been seeing many choppers lately. I was scared sh**less this am. Live 15 min from O'Hare but there was one plane flying above my house and that sucker was so large and visible thought for sure...kaboom!
OK, speaking of helicopters... three military choppers just flew east over my office in the Spokane valley towards Idaho.
This may not sound like a big deal, but it is pretty unusual around here to see a single military chopper, much less three flying in formation... weird coincidence with the chopper discussion earlier.