Were there more storms this summer or are we just getting better at taking pictures of them? We asked the experts - Toronto Star

It felt like a more intense thunderstorm season than usual, but was it really? It might be that we just got better at documenting them.

The type of storms we experienced in Ontario this summer were unique: They were bigger and covered more of the province than usual. They were also longer, stretching on in some cases for hours before tapering off, according to weather experts who spoke to the Star. At the same time, the way we’re perceiving storms has changed due to social media, making major weather events feel more acute than they may have in the past.

The summer felt particularly thundery — but that’s not reality, said David Phillips, a senior climatologist with Environment Canada. Instead, there were more intense instances of rain and thunder over a short period of time, marking memorable weather events, which are likely to stick with people.

It’s likely that when dark skies arrive, people are inclined to photograph it and post on social media, said George Kourounis, a storm chaser and explorer in residence with the Royal Canadian Geographical Society. The result is that storms have entered our collective consciousness. “Our perception has certainly changed because of the types of storms and because of our ability to share our information.”

Phillips said he would categorize the period from May through September as warmer and wetter than usual — but still not record breaking. In a usual year, based on historic averages, we’d expect to see approximately 27 days where a thunderstorm was recorded, and 33 thunderstorm hours over that time period, he said. This summer, Toronto Pearson Airport recorded just 17 days with thunderstorms, but 29 hours of storms over that same time.

Most of those storms coalesced in the late summer, between the end of August and early September, Phillips said. Specifically, a storm which ocurred overnight from Sept. 7 to 8 accounted for nearly 52 millimetres of the month’s rainfall (historically, the September rainfall total is around 74 millimetres) and five hours of thunderstorms. Five hours of stormy weather is interesting, he added as usually a thunderstorm is a “one hour wonder” that rolls in and moves along quickly.

Despite the lower-than-usual number of storms in Ontario this year, Kourounis said we’ve seen several “synoptic scale events,” which refers to long lines of storms that stretch horizontally across long swaths of the province and sweep up from Michigan and Lake Erie.

Since the storms sit lower in the sky and stretch across so much of Southern Ontario, more people in the province are impacted by a storm event at once, he said. “It’s like a giant broom sweeping across all of Southern Ontario and all of its inhabitants.”

The effect is that people think there are more storms, despite the fact that Ontario is having a slightly below-average year, Kourounis said.

Meanwhile, ominous and highly photogenic shelf clouds — the wedge-shaped clouds which roll in from the horizon and indicate a thunderstorm is coming — prompt people to take photos and post them online, he said. With social media influencing the way we regard the world around us, it’s not just that climate and the weather are changing: our perception of it is, too, Kourounis said.

While thunderstorm season was not so widespread as we came to believe, tornado season was an outlier — especially near Lake Huron, said David Sills, the executive director of Northern Tornadoes Project, which tracks tornado occurrences in Canada.

The project recorded 14 tornadoes in Ontario this season that rated above an EF-2 in severity, meaning they were considered significant and capable of serious property damage. Of those, seven happened in just one day. The number breaks a previous season record set in May 1985 during the Barrie Tornado Outbreak, when 14 tornadoes of varying severity hit Ontario. (Some of the 1985 tornadoes rate below an EF-2 and are considered weaker than the 14 significant tornadoes recorded this year.)

“That’s fairly significant,” Sills said. Outside of the province, only five tornadoes were recorded at EF-2 or higher, making Ontario Canada’s tornado hotspot.

Meanwhile, while mid-June through mid-August is typically the busy season for Canada’s tornadoes, there were virtually none documented in Western Canada, marking an intensely quiet season in the prairies, an area that would typically see several tornadoes each summer.

“We’re going to be studying this more closely,” Sills said, noting there has not been a year since the 1950s that the prairies have gone without a tornado. “It’s really unusual.”

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While Phillips cautioned that we may be finding more tornadoes than usual as a result of better technology with which to track them, Sills said the year was still an abnormality. Nova Scotia, for example, recorded two tornadoes.

“They haven’t had a documented tornado out there in more than 20 years.”

For Phillips, this summer and early fall presented “a dry run” of what the summers may look like with climate change. “I think the extremes are going to get wilder,” he said. “In many ways it was a classic, textbook example of the kind of things we’re going to see in the future,” he said of the heavier single-day rainfalls and the warmer overall summer.

For each degree of warming, the atmosphere can hold eight to 12 per cent more moisture, Phillips explained.

At three-degrees celsius of warming, a worst case scenario climate marker that we could plausibly hit without urgent mitigation measures, “garden variety” thunderstorms will soon offer us more rain than we’re prepared for, Phillips said.

Jenna Moon is a breaking news reporter for the Star and is based in Toronto. Follow her on Twitter: @_jennamoon

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Were there more storms this summer or are we just getting better at taking pictures of them? We asked the experts - Toronto Star
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