The higher you go, the less damage is done. It would take large numbers of these EMP’s to knock out the grid. The Soviet Union tested it on their own people.
Terrorists hitting power substations or embedded viruses is more likely. California is particularly vulnerable.
Appy —
Actually, there is an optimized altitude that varies slightly by yield and nature of the weapon. That’s about 40-50KM.
So if you were to go REALLY high, then yes, the damage is lessened. But in this case a nuclear device of the right sort optimally excites the atmosphere for the Compton effect at about 40-50KM, and it’s a line of sight effect from there. The pulse is strong enough that the general rule of “energy dissipates proportional to the cube of the distance” doesn’t matter here. If you’re in the line of sight of a nuclear EMP, your unshielded IC’s are screwed by HEMP.
The SHREMP pulse of a low altitude burst is devastating, but a much smaller radius, and is a direct-effect killer, no Compton effect add on.
They both suck really bad. That’s a net.
I’m with you. The grid is going down at some point but its way more likey to be a cyber attack or blackouts due to shutting down 292 coal fired power plants. If so electronics will not be destroyed. If you have an alternative electrical system such as solar you will still have power at your house. Cars will run but gas will be a problem. It will take awhile to get generators up and running at gas stations. Long term outage will be a major pain in the butt though. We are putting in solar and converting all appliances to propane.
I experienced that first hand when some dunce in AZ mishandled some switch equipment and left all of southern CA without power for almost 10 hours. I was locked in a computer room with racks of machines at the time. The power and air conditioning failed, but the racks continued to operate on the UPS. Oh crap. They're going to overheat. Now I'm obliged to open the door and stand guard to protect the machines while the other system admin looks for a way to hook up a keyboard/mouse/monitor to one of the rack machines. Oh joy. When all were shutdown, then the 7 mile ride home through bumper to bumper traffic with no traffic controls was a real mess. The only bright spot was being able to "land split" for 7 miles through dead stopped traffic on my motorcycle.
I have a small UPS in the room that I rent in San Diego. It was sufficient to keep my cell phone alive for access to current status. The Verizon cell network had good power backup and provided continuous connectivity during the outage.