Any long storm really.

A few years ago in Vancouver a storm caused quite a number of major but localized power outages, some of which took a few days to fix. During that month or so there were a few weeks where the sun was blocked for almost the entire day - not even like overcastt.

That being said, I'd you're in a more inland area, with more sun and less clouds it might make sense.

In that case put your groceries on the back porch.

That might work for food in the freezer, as long as you don't live in an area with wildlife like bears and raccoons. It seems like a huge market for this would be off-grid people, who are going to live in the country where such animals will live. It seems like raccoons are in most American cities anyway.

You are still going to have a problem with refrigerated food - lots of vegetables spoil when frozen and frozen milk isn't much fun. Plus the house is going to be consuming lots of power from lighting and TVs as days go by.

I have family that live in very rural areas. Most of them have diesel generators or tractor PTO generators to cope with power outages that last many days. Such a situation is certainly is something that is survivable without a generator, but not very pleasant. Going through the experience once, many people realize that generators aren't that expensive and buy one to be prepared next time.

You might also wonder about running out of diesel fuel, but most farmers have 500 gallon tanks of (untaxed) diesel for equipment. Hundreds of gallons of diesel lasts a long time.

And if you have something like a dairy farm, a generator is a necessity for such a situation with a milking machine.