Have not seen this mentioned on the RR boards.
GRIDEX is an exercise including local,state(law enf) federal agencies,military(US and Foreign)..
along with over 100 other private participants.
The exercise is scheduled to simulate a massive powergrid shutdown due to cyber attack,EMP
solar flare,what have you.
The areas involved cover much of the east coast.
From what I gather,it is geared towards testing communications and logistics among the players.
There may also be smaller scale drills,local or state level with federal players,private contractors and other participants(simulating threats or attacks) and the response to said scenarios.
Program and monitor your radios.May be some good listening..