An avalanche is a rapid flow of snow down a hill or mountainside. Although avalanches can occur on any steep slope given the right conditions, certain times of the year and types of locations are naturally more dangerous.Avalanches can be triggered by wind, rain, warming temperatures, snow and earthquakes. They can also be triggered by skiers, snowmobiles, hikers, vibrations from machinery or construction.An avalanche on Mount Huascaran, Peru, buried the town of Yungay in snow and ice in May 1970. The incident killed approximately 18,000 people. – North Ossetia, Russia. At least 125 people were killed as the Kolka glacier collapsed on the Russian village of Nijni Karmadon in September 2010.