The Probability of a White Christmas in Canada

Canada is well known for its white weather when winter comes and anyone will tell you to invest in a parka if you’re staying for any length of time during the season. That said, there’s no guarantee that any of the major municipalities in this country will experience snowfall on Christmas day each year. It is, however, possible to suggest which provincial capitals may receive the most snow during the holiday season and possibly have a white Christmas.

One way to tackle this subject is to take the direct approach and look at the amount of snowfall received by each provincial capital in a given December.

20121209134923

The western provinces tend toward lesser amounts of snowfall as the winter months begin. Victoria is no surprise, what with relatively warm temperatures through the month (the average low for December is 3.2°C and a daily mean is 5.2°C), due to the moderating effect of its maritime climate. Contrary to what one might think, Victoria receives very little precipitation as a result of a rain shadow effect produced by the Olympic Mountains to the south. Much of the Interior Plains receives nearly three times the snowfall of Victoria, but the continental climate of the region produces very cold temperatures in the winter months, which prevents large amounts of precipitation. The Westerlies, that blow from the Pacific across the Rockies, lose much of their moisture by the time these winds reach the plains; cold air from the arctic can also play a role in the region’s relatively low moisture levels.

As we move east across the country, the levels of December snowfall rise significantly. Quebec City receives the greatest amount of snow and is influenced by it’s humid continental climate, which lends itself to cold winters and moisture laden air from the  St. Lawrence. The east coast capitals receive significant snowfall, albeit less than Quebec. Maritime air masses bring moist air through the Atlantic region allowing for the potential of snow in December, when mean temperatures in Halifax, Charlottetown, and St. John’s are -1.3°C, -4.1°C, and -2.2°C respectfully. The coastal waters prevent air temperatures from becoming so cold as to hinder precipitation levels and thus contributes to these high levels of snowfall nearing the Christmas season.

The snowfall levels mentioned above are an effective method of predicting the possibility of a white Christmas in major Canadian urban centres, but this data says nothing for frequency of snowfall. It’s entirely possible that much of this snow can fall earlier or later in the month of December and  be the result of one or two instances of significant storms. To help predict which capitals have the greatest chances of snow on the 25th of the month, we must consider the average number of snowy days for each site.

20121210033615Again we see a similar pattern in frequency of snowfall: the far west and far east coasts of the country are polar opposites (see what I did there?) when it comes to the number of snowy days each capital experiences. This pattern is most likely a result of the same climatic factors that produce the relative levels of snowfall. We see Atlantic Canada receiving an average of just over 16 days of snow (defined as any day receiving a minimum of 0.2 cm) and are only beaten out by Quebec City, as was the case in the previous data set.

On the information above, it seems that the provincial capital most likely to have a white Christmas is Quebec City, followed by St. John’s and Halifax. As a side note, the single snowiest place in Canada is actually Mt. Fidelity in Glacier National Park, BC where the annual snowfall is 1471 cm, or 48 feet. Some of the mountain areas of the west can receive incredible levels of snowfall at high altitudes on their windward sides, as is certainly shown in this case. Since the place is uninhabited, it hasn’t counted for the purposes of this post.

All this is, of course, a general pattern that has been illustrated by Environment Canada snowfall statistics kept for the last 42 years and only reflect a possibility of snow on December 25, but it does give some sort of answer to this particularly seasonal wish that many hope to see come true each year.

(Sources: Environment Canada, Wikipedia, Current Results)

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