avalanche, não nuvem

An avalanche, released by the Swiss Federal Institute for Snow and Avalanche Research, gathers force as it sweeps downhill in the Vallee de la Sionne near the mountain village of Anzere in the southern canton of Valais, February 17, 2005. At its Vallee de la Sionne test-site the institute experiments with artificially released avalanches to gather data on velocity, pressure, flow height