Of course you can put together a list of a hundred items you might need to weather the storm, however, there are only five items that are critical to your survival:
- Medications. If you rely on medications for sustaining your life, make sure you always have a couple month's supply on hand.
- Water. For whatever reason, you might turn on the tap and the water won't flow. By having a reserve of a week--or more--worth of bottled water on hand, you will be set.
- Food. Most Americans won't starve to death in a week, they are too fat for that, but by having the barest of basic food on hand, you will weather the storm with no problem and with no reason to snow shoe your way to the local grocery store. You can literally have 21 cans of soup or 21 packets of oatmeal or 21 granola bars per person and hunger will be taken care of if you can't leave your home for a week. Simple.
- Toilet paper. While not critical, these days we don't have a lot of alternative paper products laying around (catalogs, newspapers) so while millions of people survive without toilet paper everyday in our world, most first-world people will be mighty unhappy to have to use their left hand to take care of business.
- Blankets. Obviously if you are preparing for a winter event, the more blankets you have, the better. Your heating system might break down, the power may go out, but if you have a stack of extra blankets, you probably won't freeze to death.
There is no reason that people should have to run out and get any of these items the day before a predicted weather emergency. These items can be bought and stored (and rotated, of course) any time during the year and you will be ready to meet any winter weather crisis.