Athabasca Glacier Case Study
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The Athabasca Glacier Describe the location and main characteristics of the Athabasca glacier The Athabasca Glacier is located within the Colombian Ice Fields of the Rockies. Due to recent change in climate, the glacier has receded more than 1.5 km in the past 125 years and lost just over half of its volume. The current rate of recession is 2.5 meters per year. The glacier moves down from the ice field at a rate of several centimetres per day. Due to its immediacy with Ice fields Parkway, between the Alberta towns of Banff and Jasper, and ease of accessibility, it is the most visited glacier in North America. There are usually many tours to the front of the glacier however going on top of the glacier is not recommended because there are many discrete crevasses which are typically from 30-40 meters.
The old snow is compacted due to the sufficient weight of the overlying newer snow. Avalanches are more common in the zone of accumulation. This is because it is the area where the snow is least stable. This source also has a secondary input. This is sediment. The load can vary in size; anything from large boulders that have been plucked from the Mount Athabasca Corrie to even the smallest of sediment particles from all types of moraine. Melt water makes up the majority of the Athabasca Glacier's outputs. It can form pools under and on top of the glacier and can from glacial lakes at the snout of the glacier. These pools have the tell tale blue tint due to the very fine rock flour that is as a result of englacial attrition.
The speed of this varies depending on whether it is a warm based or cold based glacier, and whether there is a large amount of ice being transported. Because the Athabasca is a temperate (warm-based) glacier, there is basal slippage occurring, which is the result of melt water running along the bedrock, therefore, the speed can be relatively fast for this glacier. Whereas the cold based glaciers do not move fast at all because of permafrost sticking them to the ground. The Athabasca falls down two icefalls in its course, these mean that the ice moving over these two icefalls moves much faster over them. Crevasses or transverse terraces which can be up to 30 meters deep form over these stretches of the ice as it moves over the ice steps. Mill holes which are similar to crevasses except they have water running through them, can be up to 60 metres deep and are also evidence that speed of the ice increases over the ice steps.
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