Permafrost, Glaciers and Sea Ice

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Abstract

Nunavut’s cold climate makes it a territory consisting of mostly barren land and permafrost. Permafrost is soil or rocks whose temperature remains at or below the freezing point for a long period of time. Glaciers, a mass of snow and ice that does not melt from year to year prevail in the Innuitian Mountains. Permanent sea ice occurs in the northern part of the Arctic Ocean.

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Permafrost

The landscape of Nunavut is marked by permafrost which occurs continuously or discontinuously throughout the territory. Permafrost is soil or rocks whose temperature remains at or below the freezing point for a long period of time. This can mean a period lasting from one winter to the next, however most permafrost has existed for much longer.

Permafrost is composed of many strata. Between the permafrost and the surface is an active layer which thaws in summer and freezes in winter. Because ice loses volume when it melts, and as the soil underneath is impermeable, this active layer is unstable and tends to collapse. This condition adds to the difficulty of building roads, airfields, public utilities and other infrastructure. Indeed, there are only about thirty kilometres of highway in the entire Territory of Nunavut. Permafrost does not inhibit vegetation, plants still grow above the permafrost throughout much of the region.

Glaciers

The same map illustrates the location of glaciers. A glacier is a perennial mass of snow and ice, formed mainly by the compaction and recrystallization of snow, that does not melt from year to year. Today the extent of areas covered by glaciers in Canada is minimal. They are found most extensively in or near the mountains along the north-eastern edge of Nunavut.

Sea Ice

Sea ice is defined as any ice that has formed from the freezing of seawater. This layer illustrates the area of the Arctic Ocean that is frozen year round - the minimum ice limit. The northernmost edge of Ellesmere Island extends into this ice sheet. During the fall and winter months the ice sheet often extends much further south, as far as Hudson Bay, leaving almost the entire territory of Nunavut surrounded by sea ice. An animation created with data provided by Environment Canada’s Ice Service. The animation illustrates the extent of seasonal sea ice in the various months of the year.