I keep my little 1 ring gas canister stove for camping in the garden shed all winter, and my supply of gas canisters - just in case (most of the camping gear is in a storage unit about 10 minutes away by car). But as a neighbourhood, we have done communal BBQs using 3 gas BBQs on the green out the front as fun events in the snow in previous years. So I try to make sure I have some gas in the BBQ as well at the end of the summer season.
I recently also bought a Kelly kettle - so I can heat water and cook using a tiny fire (just sticks - from under the trees around the green if necessary). My inclination is to boil up the water and decant into a thermos, until all 3 of my thermos' are full first, and then heat water for my tea or whatever after that. To make the best of the fire.
Tinned food that can also be eaten cold is great. Like tuna or sweetcorn. Tined soup to quickly heat is also great. Or dried noodles that need very little cooking (sometimes just boiling water) or stuff like couscous. Some are specialist camping things - but things like Koka noodles (other brands are available) or Knorr do carbonara or mashed potato with bacon in tubs just needing rehydration etc. Some microwave meals could also work with just some boiling water instead - like Uncle Bens curry pots or Dolmio pasta pots (the kind with the sauce attached to the pot of rice/pasta).
Try not to open the fridge/freezer often if the power is out. If you have any idea it might happen, freeze any iceblocks you have to help keep the fridge cold. Or to put into a freezer bag along with a couple of high usage items, like milk, butter, juice, cheese, cooked meat etc- that can take less cold but you might want to get out a lot.
If you know this morning that tomorrow night you will cook chicken for dinner and it's frozen, take it out this morning and defrost in the fridge to do it slowly and help keep the fridge cold. Cutting meat etc into small pieces will help it cook quicker when you have limited resources for fuel (or are cooking outdoors!). If you have them, use quick cook pasta/rice, or chop potatoes into small pieces, to shorten cooking time also.
If you have an open fire, or a wood burning stove, make sure you clean it out to burn cleanly and get in enough fuel ahead of bad weather. And any ignition you need (do you normally use firelighters or sticks? Do you have enough matches?). And try to keep it lighting so that the background heat is kept in the house - it's far harder to reheat from cold than it is to maintain heat so keeping a small fire going all the time may feel wasteful but often isn't especially in very cold weather.
Try to heat the immersion if there is a big storm or bad snow coming - especially if you don't have a back boiler to heat it from a fire/stove.
If you have blankets and throws, get them out for when you are sitting around. And also spare gloves and hats for playing outside - a pair of rubber gloves over woolen ones, or ski gloves, are great for DCs playing a lot - but otherwise have a few spare pairs for when hands get wet and cold to dry out 1 pair indoors while they are playing again outdoors in another. And the same for hats.
Adults love a hot cup of tea when they come indoors. We have often given hot squash (orange or blackcurrant squash made using hot water instead of cold) in bad weather and it is much-loved! Hot chocolate is also great - but many are made on hot milk. Some of the cheaper brands have milk powder in them, so are made up using hot water - in Cubs we use the Lidl version, making it up on hot water but adding cold milk to it to cool it and add milkiness too, and the Cubs really like it once there's enough chocolate in it (it does take a lot of powder).
I have a solar powered light, that is handy for times like that. Wind up torches and battery torches. I also find that having a few nightlights lit in the sitting room (safely in proper holders) can also help to heat up the room as well as giving light, and I have a couple of pillar candles that I put in lanterns so they can sit in the kitchen, as well as a collection of 3 "dinner candles" on the dining table in their holders.
But I also close off any rooms that we are not using. So in the daytime, the doors are closed to all the bedrooms and we all congregate downstairs with the fire lit. I will close the doors to the hall - but probably keep them open between the sitting room and kitchen/diner/playroom if there is enough heat (if the heating is off and I am low on wood, we'd probably keep to a single room). And when we go to bed at night, we bring hot water bottles and close off every room to keep the heat in overnight.
And have lots of board games, books and a pack of cards to stave off boredom if the power is gone. (Although I would quite happily just knit or hand-sew, the rest of the family would not do that!).