For those who have never had to think about this, it can be daunting.
But the idea is to have a few extras, that are shelf stable or frozen, of the kinds of foods you and your family normally eat. And an alternative way to cooking them if your power/gas were out.
So if you normally make your pasta and tomato sauce fully from scratch, add an extra couple of tins of tomatoes to your cupboard. But maybe also think about having 1 or 2 jars (as cheap or as high end/organic as works for your family and your budget) so that if the power is out, you still have something easy and quick to cook. The same with curry or chilli and rice.
Alternate sources of cooking could be a 1 ring camping stove (that you already have for camping/picnics - or autumn is a good time to pick up as stores try to get rid of camping gear to make space for ski gear (outdoor stores) or bicycles (eg Halfords). Or a gas BBQ in the garden - we use ours for all sorts and have used it when the power went out. A charcoal BBQ would also work but takes more effort and is less consistent in cooking…but if that’s what you have, it’s better than nothing. Do you have a small fire pit and could that be used safely?
And also think about what can make bland food taste better - herbs, spices, cooking in stock rather than plain water, having sauces that work for your family (ketchup, mayonnaise, secret sauce, chilli, Caribbean, bbq….).
What do you normally drink and do you have some bottled water for drinks? Could some squash and fizzy water work instead of normal pop?
Do you have a flask so any water you can heat can be kept hot (you might be able to get a kettle boiled in a neighbours house, or boil a large pot but only need 1 cup now but later on want washing up water)? Do you have some paper plates (even leftovers from kids parties) so you don’t need to do a lot of washing up?
Do you have a rainwater barrel in the back garden that you could use to fill a watering can or bucket to be able to flush toilets?
Do you have any power banks to recharge phones (eg for holidays)? Could you get into the habit of keeping them charged up, especially if bad weather is forecast?
It’s not about buying loads of things and having a massive stash - just thinking through how your family, in your location, would manage if the power went out for a few days or there was flooding or a lot of trees came down blocking you in…and having a few sensible things done to deal with those situations before they happen.
And if bad weather is actually forecast, I tend to try and get organised beforehand by charging my devices and powerbanks, getting laundry washed and dried, making sure I have 1 spare bottle of milk and some bread and fresh fruit/veg in the house, and also clearing away clutter on the main paths through the house to prevent trips and falls in low light conditions.