1. Define the following: Depth Hoar__________________________
Firn________________________
2. List two components, which are essential to the formation of an
ice crystal:
________________________________________________________
3. Under what kind of conditions does a Stellar Crystal form?
________________________________________________________
4. What two types of crystals form in high cirrus clouds with low
moisture and colder temperatures?
________________________________________________________
5. What is sublimation?
________________________________________________________
6. What are the two major factors that influence snow on the
ground?
________________________________________________________
7. Define Destructive Metamorphism. Does it depend on a
temperature gradient?
________________________________________________________
8.What is Depth Hoar and where is it typically found in the snow
pack?
_________________________________________________________
Part III. Essay
To survive the harsh climate of Alaska, animals and plants have
developed physical and/or behavioral adaptations to the cold, snowy
winter environment. Write a paragraph describing an observation you
have made or something you have learned about how a plant or animal
has adapted to interior Alaska's winter climate.
find in the snowpack:
a. Is impossible to determine within the snow
pack.
b. Equals temperatures throughout the
snowpack.
TERMS:
Ablation: Any process by which a glacier loses mass
including melt, evaporation, sublimation, and calving.
Accumulation Zone: The portion of a glacier situated below
the equilibrium line where ice and snow melt exceed snow
accumulation.
Advancing Glacier: A glacier where the accumulation zone is
growing faster than the melting in the ablation zone. The net result
is that the glacier is gaining mass.
Brittle Deformation: The fracturing of surface features of
an ice mass resulting from the ice traveling rapidly or over extreme
terrain. A crevasse is a good example of brittle deformation.
Basal Sliding: The sliding of glacier ice over bedrock; a
process usually facilitated by the lubricating effect of melt water.
Ductile Deformation: The bending of a flowing ice mass that
occurs in such a way that the ice itself changes shape with out
actually fracturing the surface.
Equilibrium line: A boundary between the accumulation zone
and the ablation zone where the glacier is not gaining or losing
mass.
Firn: Snow in the state of transition to glacier ice. This
rounded, well-bonded snow has survived more than one year of
ablation. It has a density greater than 550 kg/m3 (35 lb/ft3).
Glacier: A mass of ice derived largely from snow and
continuously moving from higher to lower ground or spreading over the
sea.
Ice Sheet: A dome shaped mass of glacier ice that covers
surrounding terrain and is greater that 50,000 sq. kilometers (12
million acres) . Greenland and the Antarctic are good examples of
places with ice sheets.
Moraine: A mound, ridge, or other distinct accumulation of
glacial till.
Mountain Glacier: A glacier that is confined by surrounding
mountain terrain.
Retreating Glacier: A glacier that is melting faster in its
ablation zone than the snow that is accumulating. The net result is
that the glacier's mass is shrinking.
Surging Glacier: A glacier that experiences a dramatic
increase in flow rate, ten to one hundred times faster than its
normal rate. Usually surge events last less than one year and occur
periodically, between fifteen and one hundred years.
Terminus: The lowest end of a glacier. Also called the
glacier toe or glacier snout.
