We investigated the creep behavior of alpine snow in an effort to help understand and predict the timing of ava- lanche release. The rate of deformation increases with temperature and is especially rapid in the presence of liquid water.
Creep rates decrease rapidly as the snow densifies.
The slope- parallel shearing component of motion is much smaller than expectedfrom the usual constitutive assumptions for snow. It is well known that avalanche activity usually increases at the onset of rain, long before liquid water has penetrated to depth. The analysis predicts slope failure is more likely if the overlying slab is thin and the stability is already close to critical. Field observations of behavior at the onset of rain support this prediction. Most measurements have been madein well settled snow, and here we presenthigh reso- lution measurements of deformation within low density snow.