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.
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