People are quick to panic

I’ve noticed that whenever the weatherman calls for bad weather that the stores quickly become congested with shoppers who are stocking up on their emergency supplies.  Bottled water, toilet paper, batteries, and the like.  I find it rather amusing because we always have a good stock of emergency supplies at home.  I don’t understand why so many people don’t do the same thing and wait until the day before a storm to panic and run to the store to stock up.