The only way to be self-sufficient in these situations is to own a generator. Having access to your own, immediate power is a necessity in this world of data and smart phones. However, this brings up so many more questions. How big of a generator can I afford and how large should it be?
It really depends on the number of people you are supporting and the number of devices you need to run. How many watts to power for how long? This site HERE has a handy way to calculate what you might need and even suggests getting a little larger. Like other devices, have you ever complained about having too much power?
My family had rented a beach house after a small hurricane recently that had a small backup generator. We were excited to find it in the garage. But then disappointed when it would only power the radio and we had to take turns charging our phones. At least it was there to power the coffee maker in the morning! So, it takes investing in the size, and expense, to get what you expect.