After several kilometers of walking up from the base of the Athabasca Glacier I see this icefall, its dense core gleaming a cold blue-green under a coating of crumbled surface ice and rock dust. The glacier, many tens of meters thick, pours slowly over a ridge in the earth beneath. As it does, it calves off pieces of itself ranging from small chunks to huge seracs. The jagged formations look like the spines of some massive dinosaur, extinct as indeed the glacier itself will be likely within my lifetime.