SNOW- WAVES AND SNOW-RIPPLES 133 



adhesion of the drifted particles to the windward 

 cHffs and no accumulation of them on the lee side, 

 where there is but little shelter. Six transverse 

 erosion-ridges had an average wave-length of 

 13*75 inches, the wave-length being twenty times 

 the height. The average variation of wave-length 

 from one ridge to the next was 2r5 per cent. 

 In another case a single erosion -wave was measured 

 across seven sections, giving an average wave- 

 length of 12-95 inches, which was 15-62 times 

 as great as the height. 



Four erosion-waves in unstratified snow on the 

 smooth ice of the Assiniboine River had an average 

 wave-length of 23-7 inches, which was 19-2 times 

 as great as their height. 



In the following series, of which a diagram is 

 given showing the stratification (Fig. 10), the 

 length and height of each wave was measured :— 



Measurements of a Group of Erosion-waves in 

 Compact Snow. 



Average variation of wave-length = 20-2 per cent. 



