136 Years of Snow

We've now had our second major snowfall of the year, and so I guess that it really is time to take a look at Edmonton's history of snow.

As usual when dealing with precipitation, this is going to be a mix of Edmonton Blatchford (data from 1881-2007) and the Edmonton International (data from 1961-present). I never know exactly how accurate Environment Canada's snowfall numbers are, but we're going to be looking at over a century of data, and so even if there is some variation this should at least give us a sense of how things work.

So here are the yearly snowfall totals for recorded history:

Yearly Snowfall

The 5 highest and lowest years for Blatchford are labelled to give some context.

The highest ever was 1935 with 287cm. That was 50cm more than any of the other years, and more than 1m more than we'll see in a typical year.

For the lowest years there are several around the 50cm mark. It's tough to know if those were all truly that low, or if possibly some measurements were missed? But with 5 years all in the same range, and several more around 60cm, that seems to be reasonably accurate as a floor.

Other than the outliers, most typical years are in the 80cm to 180cm range.

Yearly data bounces around a lot, so here is the same data with 5-year averages added on top:

5-Year Average

Here we can see that the average has been reasonably consistent around the 130cm mark, with a few highs and a few lows.

The very lowest years are the 1880s, and once again I have to be a little suspicious about the accuracy of those earliest measurements. Although at the same time, when we looked at first snowfall we saw that the 1880s had several years with very late first snowfalls, so it's possible that those years really did start late, and just didn't get much snow. Or it's possible that they missed some readings. There's no way to tell if it's accurate, but at least it's consistent.

The 5-year averages also make the differences between Blatchford and the International easier to spot. In the mid-1970s the International recorded more snow than Blatchford, but then in the mid-1980s Blatchford recorded more. Generally though, they were pretty similar.

There doesn't seem to be any prominent trend over the last 136 years, so now lets look at more recent history:

Recent History

So here we have the yearly snowfall on the bottom, and at the top in the red & blue is the relative warmness of each year (which comes from this post about the 20th Century Average temperature).

We are going back to the 1980s in this chart, because several times on this blog we've seen that the 1980s had some of Edmonton's warmest years. I don't think that people remember them that way though, and in the past I have wondered if maybe the 1980s were really snowy? So that even though they were warm, maybe the snow shaped peoples' perceptions of the winter, rather than the actual temperatures?

But it turns out that, no - the 1980s were not particularly snowy. 1982 was indeed the 4th snowiest year, but then 1987 and 1988 were 5th and 3rd least-snowiest respectively (and 1981 was the least snowy year ever recorded at the International).

I don't want to read too much into things, but Edmonton's #1 and #2 warmest years - 1981 and 1987 - both had very low snowfall at around the 50cm mark. And the two recent years that were notably cold - 1982 and 1996 - were both on the high side of things and approaching the 200cm mark.

Update:

After I posted this, I realized that I was grouping the snowfall by calendar year, although it really makes more sense to look at individual winters instead. Counting things as October-April would be much better than January-April & October-December.

So I'm going to redo this whole post with that shifted perspective.

Snowfall Each Winter - Version 2

With this change our top and bottom 5 have shifted around a bit.

The top 5 are now all in the range of 221-239cm, and for notable recent years 2002-2003 is still in third place.

The very lowest year is 1888-1889 with 23cm, but I'm going to assume that there is a good chance that there are some missing readings there. Next up is 2000-2001 with 38cm, and then several years in the 45-55cm range. Last winter 2015-2016 had 53cm at the International which puts it right in line with the bottom 5.

5-Year Average - Version 2

The averages change a little bit, but not very much. This makes sense, since it's a a 5-year average and we're only effectively shifting things by 6 months.

Recent History - Version 2

This chart of recent history gets a little bit more complicated, because at the top we have calendar years, and at the bottom we have the winters. So the winter of 1981-1982 was pretty snowy, but 1981 was a warm year and 1982 was a cold year - it's tougher to line things up or draw any conclusions (tougher, but I still prefer this approach).

Earlier I'd asked if maybe the 1980s were really snowy? And looking at the numbers this way, the answer is still "not really." 1981-1982 and 1984-1985 were up there, but everything else was pretty unremarkable.

In general then, in the last 35 years we've bounced around in the typical 80cm to 180cm range, with a few 50cm years, and a couple of 200 cm years. And in just the last 10 winters we were consistently right around the 100-150cm range, except for 2015-2016 down at 53cm.

So between these two approaches, I think that breaking things down by winter makes the most sense, since it's what we really experience. And that's how I will handle snow in the future.