Snow Formation and Avalanches : Page 194

Flow of water through strata.—The stratification of snow has further effects during a thaw. If the snow i& melting, or if water is running down through it because of thawing conditions higher up the slope, then one layer of snow may become wet while other layers remain unaffected. In filtering through snow, water tends to saturate a densely compacted layer such as a wind crust, in preference to traveling through a looser snow texture, and it may rise up through the layer from the bottom rather than flowing down from the top. This is because the water motion is governed primarily by capillary attraction, which tends to make it flow along the crystal surfaces, just as kerosene flows up a lamp wick, or ink into a blotter. Water in a snow layer not only reduces the internal cohesion, but also tends to provide a water-