Shedding just one drop of water at a time glaciers containing enough water to change ocean levels can melt and disappear. The glaciers of Alaska have been around for a thousands of years. However, aging the Alaskan glaciers has proven difficult in some regions. The age of Alaskan glaciers is debated because they do not fall into time of expansion like lower 48 glacier (i.e. they do not necessarily expand just because of an ice age) (Pewe and Reger 1983) and there are many methods (e.g. dendrochronology, lichenometry, radio-carbon dating) to look at expansion time and range (Barclay et al. 2009, Pewe and Reger 1991 ) – from my reading it seems the methods and results have quite a few different answers to the same questions. So, although I would like to tell you how long the fresh glacier water I drank had been locked in its solid state, I do not really think I can!
South of Delta Junction, Alaska, Castner Glacier is a rapidly receding glacier, and has changed dramatically since my last time here this spring. Just see for yourself in the pictures below! The glacier is constantly collapsing on itself; its end (i.e. the terminal moraine) is rapidly melting due to summer temperatures and record levels of summer rain this season. The cave shown was photographed just 4 months ago! The large chunks of ice which ‘calved’ from the glaciers front have melted, and the ice cave is very reduced. It also has lost a lot of its beautiful blue, translucent sheen.
The hike to the glacier’s face follows Castner Creek; the creek is fast-flowing, brown, and fed by the melting glacier. It is incredible to consider that the hundreds of gallons of water which flow by each minute are created by the collection of millions of water drops. The drop becomes a trickle which form a thin, persistent thread of water. The threads intertwine to form rivulets and the rivulets meld into flowages. The valley floor coerces the flowages into a stream which flows to the ocean. What an astounding thing to consider the power of just one water drop!
The video below captures this change of water as it moves from the glacier to stream. I hope you enjoy!
The rate at which the glacier is disappearing seems improbable to me. It is the fastest I have ever seen a ‘slow event’ take place. It seems to make expressions like “working at a glacial speed” seem less appropriate. What natural phenomenons have you seen alter the landscape in a short period? I would love to hear your stories in the comments!
Although the first freeze has not occurred here yet the willows, aspens and alder have already begun to acquire a yellow-green tint to their leaves in anticipation. Flowers are finishing the blooming and purples, yellows, and whites have given way to wispy seed-heads to be carried away by a persistent breeze.
Thanks for reading everyone! Enjoy the fall colors which are coming soon!
Citations:
Barclay, David J., Gregory C. Wiles, and Parker E. Calkin. “Holocene glacier fluctuations in Alaska.” Quaternary Science Reviews 28.21 (2009): 2034-2048.
Péwé, Troy L., and Richard D. Reger. “Delta River Area, Alaska Range10.”Quaternary Geology and Permafrost Along the Richardson and Glen Highways Between Fairbanks and Anchorage, Alaska: Fairbanks to Anchorage, Alaska July 1-7, 1989 (1983): 25-38.
Reger, Richard D., and Troy L. Péwé. “Dating Holocene moraines of Canwell Glacier, Delta River Valley, central Alaska Range.” Short Notes on Alaskan Geology, Professional Report 111 (1991): 63-68.