Glaciers Today
Antarctica Glaciers
Antarctica contains 90% of the world’s ice and 70% of its fresh
water. Antarctica is covered by a cap of ice that flows slowly
toward its 22,400 km /14,000 miles coastal, reaching the sea in high
ice cliffs. Little more than 1% of the land is ice-free. With a
estimated volume of 24 million cu m/5.9 million cu miles, the
ice-cape has a mean thickness of 1,880m/6,170 ft and in places
reaches depths of 5,000 m/16,000 ft or more. Each annual layer
of snow preserves a record of global conditions, and where no melting
at the surface of the bedrock has occurred the ice can be a million
years old.
Alaska Glaciers
Alaska is treeless plain, the ground of which is permanently
frozen except for a surface melting in the summer that results in
swampy conditions. The abundant snowfall provides the source for many
glaciers. Summers are cool there, and winters, relatively mild. For
half of the year the ground is covered with powdery snow that
accumulates to depth of several feet. While the snow cover is thin,
strong winds at times create extremely cold wind-chill
temperatures.
Canada Glaciers
Flowing some 45 miles to its end in the Alsek River Valley, the
Lowell Glacier-one of the largest among more than 2,000 in Kluane-was
recently shattered into pincushion of ice needles by a surge, here
surveyed by glaciologists studying the phenomenon. Several glaciers
wind from the interior ice fields of the St. Elias into lower valleys
at the mountain’s edge. Most of Kluane’s large glaciers periodically
surge, advancing suddenly as ice pushes out of reservoir areas within
them. Kluane, is a rock glacier-till and "scree" riding a submerged
ice-core- that spills from a high "cirque" once filled with glacier
ice. Summer meltwater makes pools like a paw prints on a glacier’s
surface. Despite surges, glaciers have been in gradual retreat
throughout the St. Elias in recent centuries, leaving a legacy of
dramatic ice sculptured valleys. Conditions in the ice fields edges
resemble those that existed at the fronts of the Pleistocene epoch’s
continental ice sheets.