2018/04/15

2017-2018 Winter-in-Review: Winter City Showdown - Part 2

Last week in the Winter City Showdown - Part 1 we looked at how temperatures for the winter of 2017-2018 compared on a day-to-day basis in Edmonton, Calgary, Winnipeg and Montreal.

Part 2 is going to be another marathon, and we're going to start with one of the most important aspects of winter - Snow!

Cumulative Snow

This chart shows the snowfall totals for the 4 cities during the winter of 2017-2018.

First, a bit of house-keeping:
  • the Edmonton data here is for the International Airport, because Environment Canada doesn't record snowfall at Blatchford
  • the Calgary data is for their International Airport.
  • the Winnipeg data is from winnipeg.weatherstats.ca. As far as I can tell Environment Canada doesn't have a station which records snowfall for Winnipeg anymore, which is weird. I don't know which station weatherstats.ca uses for their data, but it's all that I can find so we're going to run with it.
  • the Montreal data is from the main Environment Canada station.

With all of that said, Edmonton got off to an early start this year with a first snowfall on September 19th, and a total of 8cm of snow in September. We talked about that back when it first happened, and it was one of the earliest first snowfalls in recent memory (2004 and 2014 were both earlier). So this year was a bit unusual, and more typically our first snow waits until mid-October and even occasionally November. Edmonton's first lasting snow arrived around Halloween, when Edmonton, Calgary and Winnipeg all saw significant snow. Montreal's first snow was in early November, but it didn't really get going until mid-December.

Once Montreal took off though, it really took off. By late-December Montreal's total had passed the three prairie cites, and by mid-January it had received twice as much snow as any of them. As of April 15 Montreal had received 251.2cm, Calgary had 173.3cm, Edmonton was at 106.5cm, and Winnipeg was at 84.2.

Next we're going to take a closer look at the snowfall for each city, including their recent averages. We'll zip through these with some quick commentary, and we'll start with Calgary.

Cumulative Snowfall for Calgary
Here we have the same chart that we were just looking at, except this time it only shows Edmonton and Calgary. After Edmonton's early start the two cities were fairly close through the end of February. But in February and March Calgary took off.

Calgary's average and recent maximum amounts are shown here as the dotted red lines. Calgary's average snowfall total each winter is typically a bit higher than Edmonton's: about 140cm for Calgary compared to 125cm for Edmonton. This winter Edmonton is a bit below average, but Calgary is well above at 173.3cm. With one-and-a-half months of spring left, Calgary is getting fairly close to its snowiest recent years of 2008 and 1997.

Cumulative Snowfall for Winnipeg

Winnipeg's snowfall data isn't great, and so there are a lot of caveat's with this chart. As previously mentioned, the 2017-2018 data doesn't come from Environment Canada, which is unfortunate. The historic data for the average and maximum does come from Environment Canada's station at the Winnipeg International, but that data stops in 2007. So the Edmonton history here is for 1995-2018, while for Winnipeg it only includes 1995-2007.

With that said, the dotted green lines in this chart show Winnipeg's average and maximum for 1995-2007. And based on those years Winnipeg's snowfall totals were pretty close to Edmonton's. For 2017-2018 then, Winnipeg's 84.2cm is 20cm below Edmonton, and below average for Winnipeg.

Cumulative Snowfall for Montreal

Here we have Montreal's cumulative snowfall throughout the winter, along with it's recent average, maximum and minimum shown as the dotted lines. The Montreal data is also missing a few years of records - from 2012-2015 - so it's not a perfect comparison, but it's close. The scale of this chart is not the same as the others, because it needed to be increased to fit Montreal's snowiest year.

Montreal's 251.2cm of snow in 2017-2018 is more than double Edmonton's 106.5cm. But as we can see in the chart that's not very extreme for Montreal, and is only about 25cm above the average. Montreal's snowiest recent winter was 2007, which had a total of 371mm. And if we look at the line for Montreal's least-snowy winter, at 150cm that was still almost 25cm above the average amount of snow that Edmonton gets.

To take another look at snow, next we're going to break the numbers up by month.

Monthly Snowfall

Here we have the snowfall for each month of the winter in Edmonton, Calgary, Winnipeg and Montreal.
  • Again we can see that Edmonton got off to an early start with 8cm in September. And again, I do want to stress that that was unusual - it was Edmonton's snowiest September since 1995.
  • Edmonton also had a fairly snowy October with 15cm, compared to 1cm in Calgary, 4cm in Winnipeg, and nothing in Montreal.
  • For November Edmonton and Winnipeg were around 20cm, with Calgary up at 27cm and Montreal down at 6cm.
  • And then in December Montreal took off with 61cm, while Edmonton was way down at 3cm.

For the rest of the winter Edmonton was pretty average. But lets take a closer look at the individual cities again:

Monthly Snowfall for Calgary

Here we have the monthly snowfall for Calgary, and the dotted lines show its recent average and maximum amounts.

We saw earlier that Calgary has had a total of 173.3cm so far this winter, which is well above the average. And this winter the well above-average months were November, December, February and March, with February setting a new recent maximum at 43cm. 

During April & May Calgary typically gets more snow than Edmonton does, so we'll need to wait and see where Calgary ends up for this winter.

Monthly Snowfall for Winnipeg

This chart for Winnipeg has all the previous caveats about incomplete data. But again, on average the monthly snowfall in Edmonton and Winnipeg are pretty similar. And the monthly totals for 2017-2018 were pretty similar too, although Edmonton had a low December and Winnipeg had a low February.

Monthly Snowfall for Montreal

For Montreal, once again the scale of this chart needs to be different from the others so that we can fit Montreal's maximum in.

Looking at the dotted line for Montreal's average, we can see that for each month from December through March Montreal's average is more than double Edmonton's. And this year in particular, for those 4 months Montreal received 227cm of snow compared to 62cm for Edmonton.

For Montreal the 86cm of snow this January was well above average, and it was close to the very snow January 1999 which had 95cm. Montreal's snowiest month since 1995 (with the caveat that records for 2012-2015 are missing) was December 2007 with 113cm.

One final thing to notice from this chart is Montreal's maximum snow for May, which is way down at 0.2cm. In Edmonton, Calgary and Winnipeg snow in May happens about half of the time. But Montreal really doesn't get snow in May, with 2016 being the only recent year to even get a dusting. So Montreal gets a lot more snow than the prairie cities, and it's crammed into November-April instead of October-May.

All of these cities might see more snow before the end of spring, and if anything really notable happens (like maybe Calgary will cross the 200cm mark) we'll check back in.

We're going to finish today by taking one final look at temperatures. Last week we looked at how Edmonton's temperatures compared to the other cities on a day-by-day basis. Today we're going to see how the winter of 2017-2018 compared to other winters, for each of the cities.

Edmonton's Warmest & Coldest "Winters" (November 1 to April 15)

This chart ranks temperatures in Edmonton for the period of November 1st, 2017 through April 15th, 2018 compared to other winter. We use this type of chart quite a bit, and if you are interested in the details behind it the full explanation is here.

We ran a version of this chart at the end of March, and at that point the winter of 2017-2018 ranked as #67 out of 138 years. That version of the chart is here. Since then though we've had the coldest-April-since-forever, and that has dropped us down in the rankings to #77. When we include the first 2 weeks of April the winter of 2017-2018 was 0.3°C below the 20th Century average, and about 2°C below the recent average.

How did this winter treat the other cities?

Calgary's Warmest & Coldest "Winters"

Here we have Calgary's warmest and coldest winters.

This year Calgary and southern Alberta were complaining that the didn't get enough chinooks, and Calgary's winter ranked as its #100 warmest. It was -1.3°C below the 20th Century average, and about 2.5°C below the recent average. That made it colder than 2013-2014, but still warmer than 2010-2011.

Looking at the warmest winters, for both Edmonton and Calgary most of the warmest winters have been in the past 40 years. But the winter of 1930-1931 is prominent for both cities, coming in 1st spot for Calgary and 3rd for Edmonton.

Winnipeg's Warmest & Coldest "Winters"

2017-2018 was also a coolish winter in Winnipeg, coming in at #82. It was 0.7°C below the 20th Century average, or about 1.5°C below the recent average.

Comparing this chart to Edmonton and Calgary, Winnipeg's winters are a bit more variable. In recent years Edmonton's two coldest winters were 1995-1996 and 1996-1997, which were both at about 2°C below the 20th Century average. Those cold winters were apparently volcano-related, and we see them in Calgary's chart at 3°C below the 20th Century average, and here in Winnipeg at 4°C below. But Winnipeg also had a very cold non-volcano-related 2013-2014 at 4°C below the 20th Century average, compared to about 0.7°C below for Calgary and 1°C below for Edmonton.

And 1930-1931 shows up again here: 1st warmest for Calgary, 3rd for Edmonton, and 7th for Winnipeg.

Montreal's Warmest & Coldest "Winters"

For Montreal the winter of 2017-2018 was just a touch warmer than the 20th Century average at 0.3°C, but that still meant it was about 0.7°C cooler than the recent average for winter.

Comparing this chart to the prairie cities we can see that Montreal is quite a bit less variable - it's warmest winters were 4°C above the 20th Century average, and it's coldest were 3.5°C below. For Edmonton and Winnipeg the most extreme winters are 6°C in either direction.

All 4 Cities Together

And when we roll all of the cities together this is what we get. If you focus on certain years - like 1930-1931, or the "volcano" winters of 1995-1997 - you can watch the similarities and differences for the cities.

The Hypothetical Horserace

And for some final nerdery, with this chart we ask: hypothetically, if Edmonton experienced the same temperatures as Calgary, Winnipeg or Montreal, how would that rank compared to a typical Edmonton winter?

This "horserace" chart is one that we've used quite a few times before, and the full details of what exactly is going on are explained here. Generally though, this tracks how much warmer each day of the year was compared to Edmonton's 20th century average - warm days get points and cold days lose them. And what we're doing here is pretending that Edmonton experienced the same temperatures as Calgary/Winnipeg/Montreal, and then seeing where we end up.

For Calgary the winter of 2017-2018 was a cool one, coming in at #100. If Edmonton had had the same temperatures each day this winter would have ranked as #57, or about the same as 1993-1994. That's not cold, but it's not really warm either.

For Winnipeg the winter of 2017-2018 ranked as #82, but with those temperatures in Edmonton it would have been down at about #131. The last time that Edmonton saw a winter that cold was in 1964-1965.

And Montreal's #57 would have been a pretty warm winter in Edmonton, coming in at about 13th spot or tied with 1999-2000.

Going back to the Edmonton chart which we saw earlier, this is what the other cities' winters would look like:


We don't want to take this chart too seriously - hence the use of "Equivalent~ish." But this at least gives us a sense of how the temperatures for what was a cool winter in Calgary, Winnipeg and Montreal would compare to Edmonton's winter history.

In Parts 1 & 2 of our Winter City Showdown we've now seen that there are a lot of different factors that make up a winter:
  • Edmonton and Calgary have a reasonable amount in common, with the main difference being Calgary's warmer winter Highs, although that difference isn't as big a deal for the Lows. The snowfall for the two cities is usually pretty similar, but some years (like this one) things can diverge.
  • Not surprisingly Winnipeg is a colder version of Edmonton, with about the same amount of snow.
  • And Montreal's winter really is very different from these 3 prairie cities, with warmer Highs & Lows, but with a lot more snow.

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