An October storm for the record books

This was about as close as you could get to a textbook Colorado low

Strong winds and heavy snowfall saw snowdrifts accumulate fast in southern Manitoba on Oct. 11.

Hmmm… I wonder what I should talk about this time around? Maybe the massive, record-setting snow- and rainstorm that struck a large part of southern and central Manitoba from Oct. 10 to 12? Now, for those who have followed my articles over the years, you will know I’m not going to try and attempt to cover all the local damages and issues. Local news reports do a much better job than I could ever do. What I’ll be looking into is more the big-picture topics, such as just how much snow and rain fell across our region; just how did this storm develop; and how big did it get? We’ll also take a quick look at how well the weather models predicted this storm and we’ll look back at other years that have seen a wet or snowy fall, then look to see what kind of winter those years had.

OK, that was one heck of a storm that brought a lot of unneeded moisture, whether that moisture came in the form of rain or snow – heavy, wet snow. Before I start on the meteorological aspects of this storm, let’s dive into just how much snow and rain fell. The table here shows the most up-to-date totals I could find. According to Environment Canada, these are still unofficial totals.

While none of the three main reporting stations (Winnipeg, Brandon, Dauphin) broke any snowfall records during this storm, a good portion of the stations located in the hardest-hit areas saw more than 50 cm of snow and did break snowfall records for either largest single-day snowfall or most total snowfall in October for those locations, at least as far as I was able to check. Carberry’s total snowfall of 74 cm was truly historical, as I believe it broke the record for the largest October single-storm snowfall. The previous record was in Brandon, where 65 cm of snow fell Oct. 7-10, 1959.

Just how big was this storm, at least beyond the obvious? I wish I would have taken some screenshots of the wind and pressure patterns of this storm during its height. Not including typhoon Hagibis, which was raging just east of Japan, this powerful Colorado low was the strongest storm system occurring across the planet at that time. It was about as close as you could get to a textbook example of a Colorado low, and as it stalled out and deepened over northern Minnesota it had a massive circulation that was not only present in the lower levels of the atmosphere, but also extended upward to near the top end of the troposphere, something we only see in really strong storms. It was truly an impressive storm!

Rain/snow line

Next on the list was just how good of a job the weather models did on this storm. We are always so quick to bash weather models when they screw things up, but rarely talk about it when they do a great job. By Monday, Oct. 7, the weather models had pretty much come into agreement that a strong Colorado low was going to develop and track northeastward toward Lake of the Woods. By Tuesday, they had come into basic agreement that showed heavy snow falling over south-central Manitoba southward into North Dakota. They showed the rain/snow line following the Red River Valley, with snow to the west and rain to the east as the counter-clockwise rotation around the low drew in warmer air over eastern regions. Then the models showed the storm maturing and stalling out on Saturday, with a dry slot moving into eastern Manitoba and snow continuing over western regions.

As the storm moved in on Thursday, we saw things play out almost exactly as the weather models predicted. The rain/snow line did end up right around Winnipeg, as the western end of the city saw 35 cm of snow while just east of the city (my place) only received five to 10 cm of snow with the rest falling as rain. Heavy snow continued to fall to the west of the Red River Valley and this snow continued overnight Friday and into Saturday, while over eastern regions the dry slot moved in, bringing an end to accumulating precipitation. Snowfall totals, which seemed almost ridiculously high in the weather models, ended up unfortunately coming in right on target.

Well, I’m out of room for this issue, so in the next issue we’ll finish up our look at this historic October snowstorm by looking back at other years that either saw big October snow or saw significantly wet Septembers and Octobers. Then we’ll look back for similar years and see if there is any pattern to the type of winter weather that followed. Stay tuned!

About the author

Co-operator contributor

Daniel Bezte

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



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