Just as Montrealers were getting used to summer-like weather, the province was hit with the s-word — that's right: it's been snowing across Quebec all day.
It's not like it's never snowed here in April before. But after a number of 20-degree days (or warmer), we're simply not having it. As we looked up at the sky and cursed the heavens, asking, "Why the f*** is this happening?" we decided it would be more productive to ask actual experts the same question.
Why is it snowing when we've been seeing temperatures above 20 degrees lately?
Dr. Djordje Romanic, a professor of atmospheric sciences at McGill University, gave us an explanation from a scientific perspective.
Basically, it's all because of "a mid-latitude cyclone" in the northeast United States so you can blame New Hampshire and Massachusetts.
As the cyclone spins counterclockwise, it's lifting warm and moist air from the western Atlantic above dry and cold polar air from the north.
"It happened that the temperature profile in these two air masses is just the right [one] to form snow instead of rain," he said.
Can we chalk it up to global warming?
Dr. Romanic told us it's "not scientific" to say a particular event is due to global warming. Rather, we'd have to look at the frequency and severity of those types of events over time.
"We can never say that 'this or that particular event is caused by global warming.' Why not? Because we cannot go back some 200 years, undo all CO2 emissions, and see if we will have snow on 21 April 2021," he said.
How does this snowfall fit into Montreal's weather history?
Dr. Romanic said that on May 9, 1983, there was a snowfall of around 5 cm in Montreal and that on April 1, 1993, there was a snowfall of around 28 cm.
"It is not extreme in terms of it never happened before. On the other hand, such weather conditions are very unlikely and can be considered as an anomaly that is not observed on the yearly basis," Dr. Romanic said.
According to Paul Walker, senior meteorologist for AccuWeather, "April is often a month of big weather swings."
He said it's "not unheard of" to have high temperatures around 16 C to 20 C followed by a cold turn, leading to some snow several or a few days later.
Based on the 30-year average of Montreal weather, he said it typically snows 3.2 days in April with an average of 5.1 inches or 13 inches falling during the whole month.
"The season's last snowfall typically happens in April," he said.
What are the chances of it snowing in May?
Walker said a late snowfall happens in May about once in a decade.
Hopefully, it's not this year.