Published on January 20, 2024 at 10:01 p.m.
Despite a recent slight recovery in ice levels on the Great Lakes, this shortage is also having an impact here. Explanations.
An effect on mercury
Western Canada has just endured an extreme cold snap: an impressive -51 degrees Celsius was recorded in the Keg River region in the early hours of January 14th. Edmonton also experienced its coldest day in history since meteorological data collection began. The old all-time low record of -33.8 degrees Celsius set in 1996 was broken by the new mark of -34.4 degrees Celsius observed on January 12th.
Although this massive cold air mass has now spread well over Quebec, it is no longer as biting as it was over our neighbor in the Prairies last week. One of the reasons is quite surprising: the Arctic air mass passed over the Great Lakes before reaching the province. Because the surface of these vast expanses of water is almost entirely free of ice, the ice-cold air warmed as it passed over them. Basically, the cold air coming from the west has weakened as the water temperature is generally higher than the air temperature in winter.
Consequently, temperatures currently observed in Quebec are milder than those recorded in the West last week. For heaven's sake, let's remember that temperatures in Quebec, even if below seasonal norms, are still far from -50 degrees Celsius.
An impact on precipitation
Low levels of ice on the Great Lakes also have direct and indirect effects on precipitation. The phenomenon of coastal snow squalls is directly related to inadequate coverage: cities like Buffalo on Lake Erie are often exposed to large amounts of snow in a very short period of time.
In Quebec, the consequences are indirectly related, as the Great Lakes, despite their distance, still have an influence on rainfall. When the ice cover is this low, systems coming from the west pick up moisture from the Great Lakes as they pass by. The amounts of precipitation that these systems bring to Quebec are therefore higher than normal.
A delay that continues?
Until recently, ice levels on the Great Lakes were so low as to be almost nonexistent: In total, only 2.4% of the surface was frozen as of January 13th.