A new classification of the snowcover is discussed, which is based upon the mechanical deformation of the natural snowcover beam. For example, a numerical factor
eA of the beam is calculated as the ratio between the deformations when the beam is assumed of elastic or plastic property; and the beam of
eA_??_1 is defined as an elastic one. Thereby the snowcover beam can be classified into three kinds: (1) elastic one, (2) plastic one for normal stress and rigid for shearing stress or (3) plastic one for shearing stress. Observed values of
eA was 6_??_10
4 and the snowcover beams may be of the property (2). Now
eA's are bound by certain maximum value
eA* characterized at the district under consideration, and therefore
eA* can be used to classify the snowcover. The value of
eA* at the beginning of March is found as 60 at Fukui district and 10
4 at Hokkaido. It was obtained also that the elastic model of the snowslide in his previous report can be applicable only for the snowcover of the
eA*'s less than 100, and that another type of the snowslide can be expected for the snowcover of
eA*'s much greater than 100.
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