I have managed IT departments that managed hundreds of locations and thousands of computers running Windows XP and Windows Server 2003, no cloud at all. And I went through several similar outages (similar in impact on our operations, not cause or impact on others). Our first priority was to get the critical computers that operated machinery running - we did that hours (1-2) after the problem started. Then we played around with the servers and network for few weeks - but critical stuff was operable, albeit with lesser capacity and efficiency.
And we were managing forests and waterways, not hospitals and human lives.
And we were managing forests and waterways, not hospitals and human lives.