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| Glaciers are very extraordinary.
They are large masses of ice
that flow slowly over land in the polar regions and in some high mountain
valleys. They
form where snow falls in the winter and doesn't melt away in the spring
and summer. Every year new snow falls on top of last year's snow and
ice making a new layer. After many years many different layers of
snow and ice pack together and form a glacier. Glaciers flow down
slopes in the ice fields and down mountain slopes because gravity
pulls it downward until the land levels off or where the temperature
is too warm to keep the snow and ice frozen. |
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Photo
courtesy of
Reuel R. Sutton © California Academy of Sciences |
| There are two kinds of glaciers, continental
and valley glaciers. As glaciers are pulled downward by gravity they
scrape across the land and damage it. With every winter season, glaciers
grow larger as long as the temperature is cold enough to keep it frozen
and if more snow falls. |
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