Prepper simply means people who prepare for catastrophic disaster or emergency in various way.
Unlike Europe where electrical grid, communication network and highway systems are dense, U.S has a geographic location isolated from those installations because of its large territory. It is hard to be alerted of disaster emergency for most of people in rural area. As a solution, they become prepper to prepare for disasters like hurricane, typhoon or any other destructive disasters by themselves to survive This is why U.S has the largest amount of preppers in the world who are three thousand one five hundred one people that are over the half of the population in U.S. Furthermore, some elementary schools in U.S oblige students to possess survival bag in the lockers. Survival bag is a bag containing essential supplies to survive for twenty two hours in a disaster situation. It can be filled with water, emergency food like cup noodles or canned foods, medicines, hats and blankets to maintain body's temperature and whistle to signal risk when isolated in small space. For example, when the extreme earthquake happened in Easter Japan in 2011, people were well prepared.
There are some preppers not only in U.S and Japan but also in Korea. Korea doesn't have much natural disasters compared to other countries, but we can't predict the future. So we have to be ready to survive in disasters and prevent from emergency by simply preparing survival bag in our house.