last winter we had 5inches of snow [unusual for where I live ] that lasted for several days, the roads were icy and our local council did not have any grit for the roads which meant the local busses were unable to run and the local shops did not get deliveries, the first things to sell out was bread, milk, booze, cigs, tp, baby supplies and tined soups, within 24 hours the shelves were empty and most stores closed except for the news agent who still got deliveries of news papers.
People were surprised at the empty shelves, kids had a ball sledging and I was greatful that there was no poweroutages, made lots of home cooked soups and checked on elderly neighbours and enjoyed the whiteness of my surroundings and wished I had a set of skis.

And that is when the population goes feral

A friend of mine asked how bad folks might get in a panic. I told him to look at how bad it gets for 'Black Friday' sales with people stampeding to get into a store to buy things they don't really need, now make 'em all hungry. Feral barely covers it. My 2 cents.

You can also play re-runs of Katrina for them...and how the meaning bad to worse really does apply