Springtime can be the ‘right time’ for really big snowstorms

When a buildup of warm, moist air from the south collides with 
cold arctic air, your snowblower can get a real workout

This map shows the total amount of precipitation that has fallen across the Prairies so far this winter (Nov. 1 to March 16). You can see that the wettest regions have been across southern Manitoba and into southeastern Saskatchewan along with extreme western Alberta. The driest regions were found north of Edmonton, southwards to east-central Alberta, and then eastwards towards Regina.
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With spring officially here, the last thing most people want to hear about is snow. But the way this winter and spring have been going, who knows?

Springtime across the Prairies tends to bring some of the biggest snowfalls of the year. Several years ago I dug into this topic, but I figured it was time to revisit it. I once again delved into the weather records and will share with you some of the biggest spring snowstorms recorded across agricultural Alberta.

Before we look at some of these big snowfalls, let’s examine why we can experience such heavy snowfalls in the spring.

For us to get a lot of precipitation, there needs to be a lot of moisture in the air. The warmer the air, the more moisture it can hold. During spring, we begin to see temperatures warm, especially to our south, and this allows the amount of moisture in the atmosphere to increase. The other ingredient we need to produce a lot of precipitation is some way of wringing out all of that moisture. The way this is done is by cooling the air and forcing the moisture to condense and fall out of the clouds. If temperatures are warm enough, the precipitation will fall as rain. But if the atmosphere can mix in enough cold air, then snow will fall.

During our spring, Arctic regions are still covered in snow and ice and cold temperatures are usually still in place, so there is still a good source of cold air. Simply put, it takes a while for the Arctic to warm up — and until it does, we are susceptible to invasions of cold arctic air. At the same time, warm, moist air often builds in from the south as the increasing spring sunshine warms things up. Occasionally these two ingredients can come together in just the right amounts to produce big-time snows.

I wish I had the time to check out the weather records for every location in agricultural Alberta, but unfortunately I don’t. So I have broken down the records by looking at the long-term weather records for Calgary and Edmonton. For this assessment, I only looked at snowfall and did not take into account any combination of rain and wet snow, as this would mostly have been recorded as rainfall at any of the Environment Canada stations.

Let us begin by looking at Calgary. April snow is not an unknown thing to residents of this part of Alberta. Looking back through Calgary’s weather records I was actually very surprised at just how many snowfall days occur during April.

The biggest April snowstorm I was able to find occurred back in 1932, when between April 20 and April 21 an amazing 49.3 centimetres of snow fell! Then, only one year later, a storm hit on April 15 and lasted through to the 17th. During this storm, nearly 46 cm of snow fell. Another 40-plus-centimetre snowstorm occurred in 1966 between April 25 and 27 when 45 cm fell. More recently, back in 2003, 38.5 cm of snow fell between April 26 and the 28th. This storm recorded the second-largest one-day snowfall total for April when 32.2 cm fell on April 26.

The largest single-day snowfall total for April occurred during the 1932 storm, when on April 21 an absolutely amazing 45.7 cm of snow fell.

Farther north in the Edmonton region, the number of spring snowfalls is not as great as the Calgary region, but the provincial capital has still seen its fair share of large April snowstorms. The largest snowstorm occurred in 1955, when between April 18 and 20, a whopping 47.5 cm of snow fell. Another big April storm hit in 1948 when 43 cm of snow fell between April 1 and 3. The third-biggest storm occurred a bit more recently, from April 6 through to the 7th of 1991, when nearly 41 cm of snow fell, with an additional 36 cm falling on April 6. This is currently the second-largest one-day snowfall record for April.

The largest one-day total occurred on April 19, 1955 when 38 cm fell. The most recent big snow event was in 2002 when 28 cm fell on April 14 and 15.

As the stats point out, some of the largest snowstorms to hit this part of the world have occurred in April. Are we going to see another big snowfall this year? I really hope not, but as the weather goes, you just never know.

So let’s keep our fingers crossed that April ends up bringing us perfect weather and that we enter May with nice mild temperatures and soil moisture conditions just where we want them to be.

About the author

AF Contributor

Daniel Bezte

Daniel Bezte is a teacher by profession with a BA (Hon.) in geography, specializing in climatology, from the University of Winnipeg. He operates a computerized weather station near Birds Hill Park, Manitoba.

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