Mrs. Degl

Exit Glacier Alaska 2006

Mrs. DeglYes, that’s me!!!!!!!!!!!

Mrs. Degl

A glacier is a large mass of moving ice that flows slowly over the land. The glacier flows so slowly that you can’t even see it move.  Glaciers are formed in high mountains or around the polar region. During the winter the snow piles up and the glacier grows. But during the summer some of the snow melts and evaporates. Year after year the snow piles up in layers. The increasing weight causes the snow crystals under the surface to become compact and turn into grainlike pellets called firn. At depths of 50 feet the firn is compressed further into dense crystals of glacial ice.     As years pass the slab of ice gets bigger and grows thicker and becomes too big to stand still. The ice starts to move down the hill. When the ice moves it is called a glacier.    During the summer some of the snow and ice melts but in some areas of the glacier the temperature doesn’t rise high enough to melt the snow and ice. Glaciers may also increase and decrease in size because of the changes in the climate around the glacier.  For example, the ice sheet on Greenland is shrinking because of the rise in the temperature in the area.

Short summary on the formation of glaciers……………………

Mrs. Degl

Exit Glacier, the only area of Kenai Fjords National Park accessible by car, is one of thirty-five glaciers that flow off the vast Harding Icefield. The Icefield is the largest in North America, and it remains as a 300 square mile vestige of the last ice age. In this park intrepid hikers can not only trek to Exit Glacier; they can also venture up a strenuous trail to the Harding Icefield. The icefield was not discovered until early this century when a mapping team realized that several coastal glaciers belonged to the same massive system. Today's icefield measures some 35 miles long by 20 miles wide. The pull of gravity and the weight of the snowy overburden make the ice flow out in all directions. It is squeezed into glaciers that creep downward like giant bulldozers, carving and gouging the landscape. Along the coast eight glaciers reach the sea, and these tidewater glaciers calve icebergs into the fjords.

Mrs. Degl

Mrs. Degl

Glaciers

Valley/Alpine GlacierContinental Glacier

Slow-moving glaciers that are wedged between mountains.

Large sheets of ice that cover whole continents.

Mrs. Degl

Glacial Features

We will now take some notes on how each of these features form.

Kettle lakes form as pieces of glaciers break off and melt.

Mrs. Degl

Striations form as individual particles carried at the base of a glacier move across the bedrock and scratch the rock.

My picture from the Exit Glacier area, shows that the Glacier moved from left to right.

Striation are really just parallel scratches on a rock. They are found all over New York as well.

Mrs. Degl

List the glacial features you see in each photo.

Mrs. Degl

Challenge: How can you account for the missing glacial features? Is it too soon for some to form? Does the past or current climate play a role in the formation of certain features?

Contour/Topographic Map of Exit Glacier coming off of the Harding Icefield