Movement On Glaciers
Movement in mountainous terrain may require travel on glaciers. An understanding of glacier formation and characteristics is necessary to plan safe routes. A glacier is formed by the perennial accumulation of snow and other precipitation in a valley or draw. The accumulated snow eventually turns to ice due to metamorphosis. The "flow" or movement of glaciers is caused by gravity. There are a few different types of glaciers identifiable primarily by their location or activity.
• Valley glacier—resides and flows in a valley.
• Cirque glacier—forms and resides in a bowl.
• Hanging glacier—these are a result of valley or cirque glaciers flowing and or deteriorating. As the movement continues, portions separate and are sometimes left hanging on mountains, ridgelines, or cliffs.
• Piedmont glacier—formed by one or more valley glaciers; spreads out into a large area.
• Retreation glacier—a deteriorating glacier; annual melt of entire glacier exceeds the flow of the ice.
• Surging glacier—annual flow of the ice exceeds the melt; the movement is measurable over a period of time.
a. Characteristics and Definitions. This paragraph describes the common characteristics of glaciers, and defines common terminology used in reference to glaciers. (Figure 10-21 shows a cross section of a glacier, and Figure 10-22 depicts common glacier features.)
M-ACCUMULATION ZONE--ABLATION ZONE-►
\ MOAT A J ~^BERGSCHRUND
SNOW + FIRN
terminal rock / / moraine
AjCEW. I GROUND /^-C^lgffi^Jk MORAINE
Continue reading here: Figure Glacier cross section
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