Possible broadside just before Christmas: quantities revised upwards

Christmas miracle?

Many ski enthusiasts and nature lovers could rejoice: an Alberta clipper could deposit up to 15 cm in places, just before Christmas Eve. While the first estimates predicted at most 5 cm, the most recent models anticipate more generous quantities.

The system will enter Monday through the southwest gates. Southern Quebec would be particularly pampered: between 10 and 15 cm are expected for the region of Montreal, Montérégie, Outaouais, Laurentides, Lanaudière, Beauce, Centre-du-Québec and Estrie. South of the border, up to 20 cm could accumulate. Remember that we speak of a broadside when a system deposits at least fifteen centimeters.

The farther north you go, the less significant the quantities would be: the Chaudière-Appalaches and Capitale-Nationale regions should receive up to 10 cm and 5 cm respectively. We are only talking about a few centimeters for Bas-Saint-Laurent and Saguenay—Lac-Saint-Jean. Since a vigorous mass of cold air gripped Quebec this weekend, everything suggests that a white carpet could brighten up Christmas Day.

The reason behind this increase in quantities

It's all a question of temperatures: when a mass of cold air dominates the province at the same time as a system crosses it, the latter deposits more snow. When the mercury is around -10°C, the snow is powdery and accumulates in greater volume. When temperatures are around freezing, the snow is more waterlogged and therefore less bulky. Thus, for the same quantity of water, the number of centimeters added to the soil is not the same.

You will have noticed that Quebec deals with particularly low temperatures: during the night from Saturday to Sunday, a minimum of -16.7°C was observed near Montreal. As for Val-d'Or, the feeling reached -34. Abitibi had not received an extreme cold warning for a little less than two years. The mercury should not exceed -8°C Monday and Tuesday in southern Quebec.