Using GPS for snow depth and volume measurement of centennial avalanche field in High Tatras

Heavy snowfall in the High Tatras at the end of March 2009 was the cause of several avalanche falls in the Žiarská valley of the Slovakian High Tatras Mountains. The resulting avalanche field was almost 28 ha. The event was classified as a centennial avalanche, one of the biggest in modern history in Central Europe. Snow pack was measured by accurate differential GPS technology. Snow depth and avalanche field volume were calculated using a comparison between avalanche and terrain surfaces. Considering the inaccuracies of the photogrammetric digital elevation model, most likely caused by vegetation, new terrain surveying was required after the snow pack melted in October 2009. The results confirmed that deep snow packs even in rugged terrain can be accurately surveyed by GPS technology.