OCR Text |
Show tensile strength of the snow, and S, is the area of periphery fracture. From observations, S is 100 to 150 times as large as Sj so that in the majority of cases nSj is only 1% of CS and therefore the periphery effect is insignificantly small in comparison to the basal effect. Consequently, neglecting nSj and incorporating static friction in the experimental measurement of C, Equation ( II) acquires the form F. = C 1 CK. ( 12) As we have shown previously ( 1962), the shear strength of newly fallen snow is related to snow density ( d) and slab thickness ( h) by the following C= i( Jh)%- I. 4JH.+ 8.7 ( 13) Furthermore, for a slope angle ( C\ ) , we substitute into Equation 8.7 and obtain the following formula for the critical thickness of a slab of freshly fallen snow h= vL The graphical dependence of h as a function of 0^ for d • 1 is shown in Figure 1. - 8- |