Avalanches occur when a layer of snow collapses and slides downhill. The five natural causes for Avalanches are, wind, rain, warming temperatures, snow and earthquakes. There are also many things humans can do to cause Avalanches such as, skiing, snowmobiling, and hiking. Vibrations from machinery or construction sites can also cause an Avalanche. The average Avalanche can travel up to 90 km/h. Typically, after one hour, only one in three victims buried in an avalanche is found alive. The most common causes of death are suffocation, wounds, and hypothermia.