Freeze-up of Sea Ice shows the typical advance of the sea ice cover
from late summer (mid-September) to late winter (mid-March). The
dates shown in the legend of the map indicate the extent of the
sea ice cover at those dates.
Map Description
Ice will form first in shallow water, near the coast, over shoals,
banks; particularly in bays, inlets and straits in which there are
no currents. Also in areas of low salinity (near the mouths of rivers).
Shallow water is conducive to ice formation because of the relatively
small depth of water that has to be cooled. The greater the depth
of high-salinity water, later the time of freezing. In fact, deep
waters may never freeze over entirely, as not enough heat can be
removed from the water during the course of a winter to bring this
about.
Formation of sea ice begins in mid-September in the Canadian Arctic and advances southward through to the onset of winter. Sea ice begins to form
in the St. Lawrence estuary around January 1st and advances from coastal inlets into the Gulf of St. Lawrence. Sea ice in Canada normally reaches
a maximum extent at the beginning of March. At that time, sea ice is usually present in coastal waters of Canada except for those of British
Columbia where warm ocean currents from the south prevent the formation of sea ice.
[D] Click for larger version, 68 KB Navigating in ice and smoke in the Gulf of St.Lawrence during winter time.
Sea Ice Animations
Two animations are created for sea ice. Each animation was presented
in two different formats: flash and html. The Atlas of Canada relies
on Macromedia’s technology for the delivery of multimedia
content. The Atlas of Canada media player will attempt to detect
whether you have the necessary software installed, and will give
you notice if you do not. In order to play the animations in flash,
you must install the Macromedia Flash Player. Installation instructions
on Macromedia Flash Player are available at Macromedia Web
site.
- Animation of the Minimum Extent of Sea Ice 1969 to 1998
presents the variation of the minimum extent of ice between each
year for the period 1969 to 1998, with a concentration of 9/10
or greater. A concentration of 9/10 corresponds to at least 90%
of the water which is covered by ice. flash
or html
- Animation of the Seasonal Change of Sea Ice presents
a normal ice season in Canadian waters by showing the normal evolution
of sea ice throughout the course of a year. The animation does
not reflect any real observed sea ice season, but rather a 30-year
statistical compilation. flash
or html
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