CME, Coronal Mass Ejection , [when the sun barfs, ] Been there , done that . The big ones are incredible .Wipe out all kinds of communications.
JVC You don't need a CME just go up the Delaware river ,in NY, Mongoup to Barryville .There is NO cellphone service [except for the Park Service system ,for their use only]. 2M amateur radio also doesn't work .for any emergency on the river or rt 97 ,you have to go up to the mountain top to catch cell phone . The NPS was supposed to provide one for us peons but Gov't agencies don't careabout us !!!