Milk and Bread

Why are they the "staple" of everyone's household shopping list during a major storm? If you didn't have milk in the house and were unable to leave for a period of time, what's the worst that could happen? So your kid doesn't have milk for a few days...it's not like that's some sort of life threatening concern. And bread? Again if you ran out and couldn't leave, would it be the end of the world? There are other things to eat besides sandwiches and toast when a storm blows through.

I have just always found it odd that when there is a storm coming, everyone and their brother runs to the store for milk and bread (and sometimes eggs).