I will sometimes get asked a question this time of year: Why, after an extended outage, does my power come back on but then goes out again after a minute or two?
Cold load pickup or, more appropriately, non-diversified load is the culprit.
Electrical load, normally, is diversified. That means that everyone’s heat and hot water tanks are not all on at the same time. My thermostat might run my heat between 10:10 to 10:20, while your neighbour’s might run from 10:30-10:40.