Landslides not only are dangerous — causing on average more than 25 deaths and over $1 billion in damages a year — but are also widespread, occurring in all 50 states. Compounding the hazards, these natural disasters often occur along with other similar natural phenomena, such as floods or earthquakes. To minimize risk, the slope of land and materials underground must be considered when planning how to build in a community. Altering the slope of land, or even the amount of vegetation on a slope, can have dangerous consequences.