The Federal Emergency Management Agency, known as FEMA, is responsible for preparing the United States for natural disasters. One way the agency works to be prepared is by trying to predict where disasters might happen in the future. The information FEMA gathers is calculated and put into a tool called the National Risk Index. The index takes a look at natural disasters such as earthquakes, floods, forest fires, tornadoes and more. It also takes population and building density into consideration. Out of over 3,000 counties in the U.S., Los Angeles County in southern California is the riskiest place to live. That is home to the city of Los Angeles.