The Knik Glacier is located 50 miles
north of Anchorage. Situated on the northern edge of Alaska’s Chugach Mountains,
Knik Glacier is one of the biggest glaciers in south central Alaska. At 25 mile long and over 5 miles across, Knik Glacier
is actually a small remnant of a past ice age. During the Pleistocene ice age
600.000 years ago the Chugach Mountains were covered in ice over 1/2 mile thick.
Knik Glacier connected to a massive ice field that extended hundreds of miles
into the ocean.
Knik Glacier is a master sculptor
carving valleys and shaping rock into landscapes of exquisite natural beauty.
Surrounded by 10,000 ft snow-covered peaks, hanging glaciers, and
waterfalls, the Knik Glacier has carved out one of
Alaska’s most spectacular natural amphitheaters.
Knik Glacier is the
centerpiece of the 17,000 acre Lake George National Natural Landmark. The
National Natural
Landmark Program recognizes over
500 sites in the United States. Established in 1962, the program aims to
encourage voluntary preservation of sites that illustrate the geological and
ecological history of the United States and to strengthen the public’s
appreciation of America’s natural heritage. In order to be selected a site must
of national significance and the best example of a regions biotic or geologic
features.
Click an image to
see it full screen.
The Knik Glacier was selected because of
a rare geologic phenomenon that occurs here called a "jokulhlaup" (an ice dammed
lake). Jokulhlaups occurred here annually until 1967. In winter the Knik
Glaciers would advance and press its mass of ice, up to 400ft thick, against the
side of Mt. Palmer and block the flow of water from Lake George. In spring the
Lake George Valley behind Knik Glacier would begin to fill with water. The 5
mile lake would swell to over 20 miles and water levels would raise 180 ft. The
Water levels would eventually rise over the ice dams and the annual breakout
would
occur. Millions of gallons of angry surging water would roar down the
valley loaded with silt, debris and glacial ice.
This natural wonder occurred annually until 1966 and played a significant role
in the lives of Native Americans and early
pioneers. The town of Matanuska had to be relocated due to the annual flooding.
Just before 1900 three Indian villages along the Knik River were destroyed by a
great flood. Transportation routs between Anchorage and Palmer would be blocked
for a week or two every year. Early pioneers held a lottery annually to predict the exact time and day the breakout would occur.
Since 1967 a decrease in glacial advance has prevented the formation of Lake George,
but a renewal of these awesome events could occur at any time.
The tremendous events caused by the advance of the Knik Glacier
have been replaced by tremendous events of a receding Knik Glacier. Knik Glacier
is on the move! In 1997 the Knik glacier woke from a long slumber. In
response to a global warming trend the Knik Glacier, like many Alaskan Glaciers,
is getting smaller. A new lake over 3 miles long and over 400ft deep
has been exposed at the glaciers face and this lake is getting bigger every
year.
18
NATIONAL NATURAL LANDMARKS IN ALASKA
Aniakchak Crater, Arrigetch Peaks,
Bogoslof Island, Clarence Rhode
National Wildlife Refuge,
Iliamna Volcano, Melaspina Glacier, McNeil River State Game Sanctuary, Midelton
Island, Mt
Shishaldin, Mt Veniaminof, Redoubt Volcano, Simeonof National Wildlife
Refuge, Unga Island,
Walker Lake,
Walrus Island, Worthington Glacier, Shishaldin Volcano.