Snow, Ice, Avalanches, and Glaciers - Mountain Geography: Physical and Human Dimensions - page 157

because of small but significant shape-related temperature differences (Colbeck 1982,
1983). The result is that large polygranular units form over time, often referred to as
corn snow. In the warm part of the day, the snow may be mechanically weak because of
the melting of intergranular bonds, whereas in the cold part of the evening, the snow
may be very strong because of refreezing of the liquid water, especially near the sur-
face where radiant energy exchange is pronounced. The process of repeated freezing
and thawing causes increased densification and consolidation and is responsible for the
formation of firn or névé, which is dense snow at least one year old. The snow may now
be as much as 15 times denser than when it first fell, and is well on its way to becoming
glacial ice (de Quervain 1963: 378).