Learned long ago from dad in the army and moving around to different bases. We had hurricanes/blizzards/tornadoes etc.in the different areas. Always try to keep cars at least 1/2 full of fuel, first aid kits, store-able snacks, and water. I also have a backpack with a full change of clothes, sweatshirt and pants, rain gear.
If you have generator buy some extra 5gal cans now. We had Hurricane Sandy here and no power for days, some places weeks. Gas stations didn't have generators to power fuel pumps. Those with power had no fuel and couldn't get deliveries. I have 10gal filled that I use for OPE. I also rotate that and use it in car every 1-2 months then refill the cans. I have 4 empty gal cans that I can fill if needed. I do that before any significant storm is forecasted as well as fill both vehicles and all power equipment. Also start and test all saws/generators at least once month. Get CASH and keep somewhere. Fill propane tanks so you can BBQ (pending your wood/firepit/wood stove scenario.
Wise Food Company has some decent meals in 5 gal buckets that can be stored for a long time.
Total SHTF and most plans will be done anyway so you'll need to work through it then. Not real expensive to be prepared for a week self sufficient almost like camping. Worst part about Sandy was listening to the wife, kids and father-in-law whine about no television. I wasn't running generator for hours just to watch movies, too bad, read a book, cable was out also for regular TV. Not knowing how long power out (mine was 4 days) Fuel was being saved to power Fridge/Freezer a couple times a day and run boiler for heat and hot showers.
Winter- cars add avalanche shovel (it folds small) some warm gear, polar fleece blankets, and some tea light candle with holder. Amazing how much heat can be generated by that small flame.