Crevasse
Written By: Alison
Usually any crack or separation in the lower layer of ice is
fixed quite fast because there is so much pressure and. In the upper layer of
ice, there is way to much tension from moving over objects beneath it or doing
different movements that it causes a crevasse. A Crevasse is defined as a large
crack in the upper surface of a glacier. A crevasse is formed when there is
tension on the brittle ice. A crevasse can usually become many meters deep. They
usually get covered by recent snow fall. There are four types of crevasses. One
is a transverse crevasse. This happens when part of the glacier all the sudden
becomes steeper. A longitudinal crevasse is where the glacier spreads over a
wide range of land, like a valley or plain. The third is a marginal crevasse.
These are caused when the central part of the glacier moves faster than the
sides and causes a lot of strain and tension. The bergshrund crevasse is a large
crevasse that is usually formed in the shape of a semicircle. It is at the head
of the glacier, between the glacier itself and the headwall of the valley that
it’s traveling towards.
A crevasse caused many problems for the polar explores. If
one of them was to fall in they usually couldn’t get themselves back out. During
light hours, people could usually see them. They spread a ladder across, and
walk over top of it. But if they are in an area where there is hardly any day
light they can’t see the crevasses and fall in.
Crevasses aren’t the only problems that are caused by
glaciers. During summer parts of a glacier can break off causing icebergs. The
icebergs can be extremely large causing problems with ships or boats traveling
the waters. They can also be very small, not causing any trouble at all. When
glaciers move they take anything that is in their path. Rocks are plowed out of
the way or broken up by frost action and then carried away. Rocks that are
beneath it break up and move the rocks below it. If the glacier was to melt it
could cause many problems in flooding.