Seminar by David Atkinson on Nov 4, 2015

Physical Stressors and the Northern Coastal Context
David Atkinson, Dept. of Geography

Many communities in the Arctic are situated on the coast; for example, 26 of 27 communities in Nunavut. Coastal location is desirable because it enables ready marine access that supports travel, resupply, subsistence, and cultural activities. Marine travel is of particular importance because there are no roads to these locations and shipment by air is expensive. However, coastal regions in many areas of the North are subject to various marine hazards, which include wave attack leading to abrasive and thermal erosion, positive and negative wind set-up events (surge), coastal ice berm formation, and ice-push and breakout events. Coastal areas of western Alaska (Bering and Chukchi Sea) and the western Canadian Arctic (Amundsen Gulf – eastern Beaufort Sea) are often hard-hit by hazards of various sorts, partly because there are particular aspects of some areas that enhance the hazard. Much of this region presents a broad and shallow littoral zone. This, combined with a microtidal regime and the occurrence of slow-moving weather patterns, can result in large-magnitude surges that are long-lasting and have the potential for inundation no matter when they occur during the tidal cycle. Positive surges also have the potential to increase depth-limited wave amplitudes, allowing for greater run-up. The occurrence of sea ice can act to mitigate wave action, but surges can occur even when full ice cover is in place. Persistent wind stress can act to mobilize sea ice and drive it ashore or move it away from shore in a “break-out” event; either can be problematic. During periods when sea ice is forming, linear berms composed of frazil- or slush-ice can form on the beach, which can reach 4+ m in height. These can act to prevent surge inundation of a town, but they can also greatly impede access to the sea. This talk will examine some of these northern coastal stressors in the context of instrumental, numerical modeling, and interview work that has been conducted over the years in coastal Western Alaska and the western Canadian Arctic.