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Arctic Coastal Plain

↑About the Arctic Coastal Plain

The Arctic Coastal Plain is a low, flat region along the north coast of Alaska along the Beauford Sea, extending eastward almost to, but not quite to the Canada-Alaska border. The region is significantly broader in the west and is very narrow in the east.

The climate is a dry, polar (tundra) climate, with short, cold summers and long, severe winters. The climate is warmest in the interior of this region, with a small zone approaching a cold semi-arid climate. The coastline freezes entirely in winter, and thaws during summer, such that the region is ocean-moderated only in summer, leading to cool, foggy conditions. Although rainfall is low, relative humidity is high.

The topography ranges from flat to gently undulating, and tends to slope gradually downward to the north. The ground is covered thinly in marine and alluvial sediments. Permafrost is continuous throughout, and melts only temporarily in summer. There is a moderate to low density of slow-moving streams, and throughout there is a high density of thaw lakes, ponds, and wetlands. Soils are mostly formed of a thick layer of organic matter, and are poorly drained not only due to the flat topography but also due to having only a thin layer of temporarily thawed soil underlain by permafrost.

There are no trees here, but there is nearly continuous cover of shrubby tundra, with dominant species including dwarf forms of woody plants such as birch, willow, northern Labrador tea, and herbaceous plants including Dryas sp., rushes, and tussock-forming sedges. The tallest growth of birch, willow, and alder is found on the warmest sites, whereas the wettest sites are dominated by arctic willow, sphagnum moss, and sedges.