Debris flows often happen in areas where excessive rain causes soil to become so saturated it turns into very runny mud. The mud then races downhill, picking up debris such as fallen branches, tree trunks, and rocks as it goes. Debris flows can bury homes under a pile of mud and debris. Know the risks of the area where you live so you can prepare your family and home before heavy rains threaten your area. weather.gov/safety/flood-hazards photo:FEMA