At the Austrian alpine village of Galtur, snow on the mountains surrounding the village build up. Due to the changing temperature during the month, a strong but brittle layer of ice forms under the snow. On the day of the disaster, the ice layer collapses and the building ice bank slips down the slope and forms a powder avalanche. Two minutes later, it hits Galtur and buries 57 people in the snow, killing 31 of them.
avalanches, never before had they occurred on such a scale as this, reaching the village. A complex sequence of events led to the event: 4000 kilometers away, on January 20, an Atlantic storm was forming. Turbulent warm air from the tropics headed north, and, cooling, it swung back towards Europe. This started a series of storms. Combined with cold arctic air coming from the north, there was a very dry, light snowfall exceeding 4 meters. A massive snowpack formed on the mountains above Galtür. Northwest winds piled the snow to increasing depths. A melt-crust developed in late January, formed when solar energy thaws the upper snow layers in the day, but it then refreezes at night. At Galtür, it bonded with ice and hence lasted longer than they were generally known to. The resulting powder avalanche contained a central layer scientists were not previously aware existed. Known as the saltation layer, it was primarily responsible for the destruction of buildings. So many people died because of the zoning. The red zone had no buildings. The yellow zone had buildings weakly reinforced in terms of 170,000 tons of snow falling. The green zone was believed to be perfectly safe, and buildings were not reinforced. Most died in the green zone. The city founders did not expect an avalanche like the one on February 23, 1999