30 Year Median of Ice Concentration charts are derived from Total Concentration of Ice values taken from the Canadian Ice Service's Regional Ice Analysis Charts on a weekly period. The 30 Year Median of Ice Concentration charts do not represent any real ice season but rather a statistical composite of all seasons covered by the regional Ice Analysis charts.

For browsers that do not support Javascript, access 30 Year Median of Ice Concentration charts in List Format.

Why Use Medians?

Consider a single data point near the edge of the fast ice in late spring. The ice conditions can be ten tenths when fast ice is present or open water after the ice breaks up. Rarely will the four to six tenths range of ice concentrations occur, which is the inevitable result if one averages between no ice and ten tenths. A median, on the other hand, will be either zero or ten tenths depending on the relative frequency of break-up before or after a given date. This seems much more appropriate for charts describing ice conditions over a 30 year period.

These maps in GIF format display "normal" ice concentrations for the periods indicated.

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Last Updated: 2008-12-09

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