At the beginning of January 2026, the ice cover is well established in the estuary of the St. Lawrence River. This is the first near-normal winter since 2020. Ice fishing was able to start early at the mouth of the Rimouski River.
It’s really the air temperature that decides everything. We have big polar vortices that bring us cold. Today is one of the coldest days of winter. This is what will form the ice
explains physical oceanography researcher at the Maurice-Lamontagne Institute, Peter Galbraith. The ice cover that has formed over the past few weeks is a little below the normals calculated over a 30-year period (1991-2020).
This is the first time in six years we’ve seen this. The last few years have been catastrophic in terms of ice cover.
About half of the water volume of the St. Lawrence River must be at the freezing point before ice begins to form in the estuary, according to Mr. Galbraith. It then progresses towards the Gulf of St. Lawrence.
If the polar vortices continue, ice could cover the entire Gulf all the way to the coast of Newfoundland. It happened very frequently in the 1990s, it happens very infrequently now.
The researcher in physical oceanography at the Maurice-Lamontagne Institute, Peter Galbraith.
Photo : Radio-Canada / Francois Gagnon
The ice cover that will be reached at the end of March will depend on how January goes and future weather conditions. The tides will have an influence on the ice cover for ice fishing at the end of the river, like in Rimouski. We are talking about a fast ice shelf which is really attached to the coast. High tides can detach it and with the right winds, it goes out to sea.
adds researcher Peter Galbraith.
Tides have no influence on the formation of offshore ice, which instead depends on air temperature. We must hope for large polar vortices to build this large-scale ice cover in the Gulf
concludes Mr. Galbraith. If the warm weather continues during the month of January, the formation of the ice cover could stagnate.
Winters without ice cover make banks vulnerable to high tides and coastal erosion. In 2024, a new record was broken: the lowest ice cover ever observed in the St. Lawrence since 1969, the start of the compilation of information on the freezing of waters by the Canadian Ice Service.
With information from Camille Lacroix
