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Comment: 03:27 - 04:29 (01:02)
Source: Annenberg/CPB Resources - Earth Revealed 23. Glaciers
Keywords: "James Zumberge", snow, "glacial ice", "snow crystal", season, compaction, firn, ice, glacier

Our transcription: So as snow accumulates year after year a glacier begins to form.
The actual manner in which snow is converted into glacial ice involves compaction and rearrangement of snow crystals.
There's a process that goes on as each layer of snow is added year by year, that's residual snow from the previous winter.
It compacts under the weight of new snowfall, and as that compaction takes place, the snow crystals are pressed closer together.
The air in the original snow pack is generally expelled by this compaction, and the snow crystals join together to form an intermediate substance between snow and ice, which we call "firn."
It's an old Swiss term that's still used today, so eventually the firn itself is more compact, more re-crystallized, and it becomes glacier ice.

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Page Last Modified: Thu Oct 31 04:27:45 PDT 2013  (chd)