Ted Kopel, formerly of Nightline, recently released book entitled: Lights Out: A Cyberattack, A Nation Unprepared, Surviving the Aftermath describes enemies of the country taking out the US electric power system by hacking their computers. He envisions months of no power, with extreme food shortages and other major consequences.
Looking at this from a supply chain / logistics perspective the potential for cyber attack seems credible, but the slow response does not. Supply chain risks is something a lot has been written about. Certainly, loss of data and loss of computer services is one of those risks. In preparing for this back up and restart procedures must be part of the planning process before any potential bad thing happens.
I have no inside information, but I am sure electric power companies have thought about this, and have back up and restart procedures in place. The US electric grid is vast and complex, just like many supply chains. That means there are alternatives available and alternate processes, and no one attack is likely to close down everything.
So planning for loss of IT services should be part of your planning in your supply chain. There will be some time frame involved for restart, an priorities are best established in advance, so you don’t have to start from scratch in a chaotic situation. Your organization cannot probably exist through a long term shut down. It is part of sustainability planning to be aware of this situation.