HALIFAX -- Recent analysis from the Canadian Ice Service has found the weekly sea ice coverage to be at record lows for both the Gulf of St. Lawrence and the broader East Coast region.
Sea ice in the Gulf of St. Lawrence is at its lowest point in the season in more than 50 years. At 1.6 per cent, the ice coverage is estimated to be a month or more behind in comparison to normal growth. The little ice that is present is mostly comprised of new, grey ice with a thickness pf less than 15 cm.
Ice conditions in the East Coast region actually fell week-over-week from 2.6 per cent coverage to 1.2 per cent as onshore winds compacted and destroyed sea ice along the southern Labrador coast.
A chart showing a same week comparison for ice coverage in the eastern Canadian waters going back to 1968. At the moment the region is at a record low.
I reached out to ice forecaster Douglas Leonard with Environment and Climate Change Canada for more on why the coverage has hit record lows this season.
While water temperatures have been cold enough to support ice development it has been the atmospheric conditions and weather that have prevented that from happening.
"The main cause this year has been the warmer than normal air temperatures across the entire East coast," Douglas said. "We’ve seen some ice start to form, and some still remains, along the coast of New Brunswick, P.E.I., and in the estuary of the Gulf of St. Lawrence, however the ice is thinner than normal and much of the ice that started to form has been mainly destroyed in the last few week due to the storms that moved across the region."
Could a turn to colder weather return ice coverage closer to normal? Not quite according to Mr. Leonard. He explains that while the extent or area of coverage could expand rapidly in a prolonged cold spell the thickness of that ice is unlikely to "catch up" given the delay in the season. He expects that there is a high likelihood that the season finishes with less and thinner ice overall.
The reduced sea ice coverage can be favourable for transportation. Shipping and ferry services have, to date, had little ice to interfere in transit. Canadian Coast Guard icebreakers are relied upon to keep lanes open through the Gulf and, so far, there has been no need for this. There are potential downsides as well. For example lack of coastal ice exposes areas to more erosion through the winter season due to wind and waves brought on by passing storms. The Great Lakes region has been lacking ice this season as well and there have been reports of localized flooding and erosion.
An area map showing the departure from normal of ice sea in the region. The darker the shade of red the greater the departure (lower) has been analysed to be.
As far as a weather impact goes. The longer the waters are open in the Gulf of St. Lawrence the more instances of "sea effect" snow that could be seen in P.E.I. and parts of Nova Scotia. That snow is generated when colder air is moved over the ocean waters, which encourages the rise of moisture from the water into the atmosphere, which is then brought onshore in the form or flurries and bands of intense snow squalls. Ice coverage over this area greatly reduces that draw of moisture.
Climate change has had an impact on sea ice conditions for the East Coast. A significant downward trend of 7.6 per cent per decade has been observed. Canada’s Changing Climate Report published in 2019 found that it is very likely that there will be continued reductions in winter season ice for eastern Canadian waters under a number of emission scenarios.
Much of the data and charts in this article courtesy of Douglas Leonard and the Canadian Ice Service.
