Lake George National Natural Landmark
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.
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 routes 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.
