1999 Galtür avalanche

The Galtür avalanche occurred on 23 February 1999 in the Alpine village of Galtür, Austria. At 50 m high and traveling at 290 km/h , the powder avalanche overturned cars, destroyed buildings and buried 57 people. By the time rescue crews managed to arrive, 31 people had died. It was considered the worst Alpine avalanche in 40 years. Three major weather systems originating from the Atlantic accounted for large snowfalls totaling around four meters in the area. Freeze-thaw conditions created a weak layer on top of an existing snow pack; further snow was then deposited on top. This, coupled with high wind speeds, created large snow drifts and caused roughly 170,000 tons of snow to be deposited.

Wikipedia