In this issue we’ll take a look at Canada’s top five weather stories from 2011. Interestingly, all five occurred, at least in part, in Western Canada.
The first and indisputably biggest weather story happened across the southern and central parts of the two provinces just to the east of Alberta. Before last winter had even started, the discussion across the eastern Prairies was about the upcoming spring flooding. The talk wasn’t about whether there would be a flood, but rather, just how bad it would be.
It all started way back in October 2010 when a huge storm system dumped upwards of 100 mm of precipitation across much of southern and central Saskatchewan and Manitoba, pushing river and lake levels to near their highest levels ever recorded for that time of the year.
Things only got worse over the winter as average to above-average snowfalls were recorded. When spring finally rolled around and the snowpack melted, water began pouring into the river and lake systems all across Manitoba and Saskatchewan. According to Environment Canada, on May 9, the Manitoba government declared a province-wide state of emergency, issuing evacuation notices for several municipalities along the Assiniboine River.
Brandon was at the epicentre of the months-long flood battle. In Brandon the Assiniboine reached its highest level since 1923 and kept rising. The river was nearly seven metres higher than normal and 20 to 30 times wider in some places. Flooding on the Assiniboine near Brandon lasted 120 days and was the largest on record.
Slave Lake fire
The second big story was the Slave Lake fire. A late forest greenup, accompanied by very dry air and high winds created the perfect conditions for forest fires. I don’t think I need to go into all the details, let’s just say that by the time it was all done the Slave Lake fire was the second-costliest natural disaster in Canadian history. Then to add insult to injury when June rolled around it started to rain, and it just kept on raining, resulting in one of the wettest Junes on record.
The third-biggest weather story of the year was tied directly into the record spring flooding and wet spring conditions, and that was the weather reversal this summer. What started out as one of the wettest growing seasons ever, quickly morphed into one of the driest seasons ever.
In Winnipeg, July was the driest month since record-keeping began in 1872. Even the most rain-soaked areas dried out by August. In Edmonton, the August-September period was the driest ever recorded. The best statement that summarized this weather was from a Manitoba farmer who said, “I could be receiving flood and drought insurance payments at the same time.”
Our fourth story, just like the third story, has ties not only to the Prairies but also is really an extension of the last story. This story was the hot weather across much of Canada during the summer and fall of 2011. The heat was a result of a large area of high pressure centred over much of central and eastern North America and it brought with it several records.
Windsor, Ont. recorded its warmest July ever, with a mean daily temperature of 25.9 C. Windsor also recorded its hottest day ever on July 21, with an average daily temperature of 32.1 C. Quebec also saw record heat with the hottest temperature occurring at St-Hubert at 36.0 C.
Our region also saw some record heat. Winnipeg recorded 24 days when the daytime high rose above 30 C, exceeding the total for the past three years combined. Winnipeg also recorded its hottest day in 16 years with a temperature of 37.2 C on August 23.
Here in Alberta the summer wasn’t that hot, but once September rolled around the temperatures soared. Both Calgary and Edmonton saw their warmest temperatures of the year during September.
Our last weather story of 2011 occurred right here in Alberta and had nothing to do with temperatures, precipitation, or flooding. This story was about the incredible winds that hit southern Alberta during the last couple weeks of November. A near-perfect setup of strong low pressure over northern B.C. combined with a ridge of high pressure over the western United States created a very strong pressure gradient. Combine this with the Rocky Mountains that help to squeeze the air flow even more, and we have the perfect setup for high winds.
This “super chinook,” as it has been called, broke temperature records across Alberta, but it was the record-breaking winds that were the real story. According to Environment Canada, surface-based wind gusts measured 144 km/h at Claresholm, 131 km/h at Stavely and 117 km/h in Lethbridge, and at a home weather station in Pincher Creek, winds were clocked at 204 km/h! On Nov. 22, wind gusts were so strong near Nanton that eight vehicles were blown off the highway and the roof of a high school gymnasium was peeled away, forcing students and staff to evacuate the premises.
Let’s hope that 2012 is a little quieter!