Been following this one for a while and yeah, the timing always bothered me. The comms blackout isn't something you can easily explain away as routine maintenance, not when it lines up that precisely with the power grid event.
What I find interesting is that a mate of mine who was visiting the Reno area at the time said his sat nav just went completely haywire for about 40 minutes before the blackout hit. GPS disruption like that usually points to something generating serious electromagnetic interference at ground level.
The Nellis range has form for this kind of thing. There were similar reports around a 2006 incident that never got properly documented in any official capacity.
Anyone got contemporaneous accounts from locals? I'm particularly interested in whether anyone experienced any unusual sounds or vibrations in the hours leading up to it. That detail tends to get lost in these threads but its often the most telling part of the picture.