Late Winter Sea Ice Conditions

Late Winter Sea Ice Conditions shows the typical sea ice types near the end of the winter season (February 26) and as well as frequency of sea ice on that date. The frequency of sea ice indicates how often sea ice has been present on February 26 over the last 30 years.

The ice type gives an indication of the thickness of sea ice. When sea ice first forms it is referred to as new ice. As winter progresses it grows in extent and thickness. As sea ice thickens it is referred to successively as grey ice, grey–white ice and first year ice. During the summer sea ice melts and any first year ice remaining at the end of the summer melt is then renamed "old ice" on October 1.

Various ice types can be present in a given area, but one of them will be predominant. The predominant ice type is the one in greatest concentration in a particular area. However, because of the danger that old ice represents for navigation, and if 40% or more of the area contains old ice then the predominant ice type will be old ice even if thinner ice in greater concentration is present.

Map Description

This map shows the frequency of sea ice and what is the most likely predominant ice type encountered near the end of the winter season (February 26). In the winter, sea ice is usually present in all coastal waters of Canada except for those of British Columbia where warm ocean currents from the south prevent the formation of sea ice. There is old ice in the Arctic and first year ice in most of the remaining waters except for thinner grey and grey-white ice in portions of the Gulf of St. Lawrence and East Newfoundland waters. This situation is normal in the winter as shown by the very high frequencies of sea ice present during the winter. In some years, with colder temperatures and strong north-westerly winds sea ice will extend further eastward and southward along the east coast as shown by lower frequencies of sea ice in those areas. The extent of sea ice in those areas is limited by the heat exchange from warmer and deeper waters offshore that melts the sea ice moving in those areas.

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Navigating in ice and smoke in the Gulf of St.Lawrence during winter time.

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Landsat 7 image, taken on February 14th, 2002, in the St.Lawrence River at Baie Comeau (Quebec)

Also shown are areas of permanent ice and the estimated maximum extent of ice observed outside Canadian waters. Areas designated permanent ice indicate where ice has been observed all year round throughout the period 1969 to 1998. The estimated maximum extent of ice outside Canadian waters displays where ice has been observed on February 26 at least once over the 30 year period.

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

• Break-up of Sea Ice Map | Read about this map
• Freeze-up of Sea Ice Map | Read about this map
• Late Summer Sea Ice Conditions Map | Read about this map

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• Sea Ice
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