Multi-day snow squalls threaten hefty totals, dangerous travel to Ontario

The first major snow squall event of the season is shaping up across Ontario's snowbelt regions, and while this will be amazing news for ski areas ahead of the holidays, drivers will be tested with dangerous road conditions

A very long duration and major, lake-effect snow squall event is setting up across Ontario. The snowbelts will certainly live up to their name and reputation during the next few weeks, with impressive, and possibly overwhelming, snow totals expected as we kick off December.

Road closures are certainly possible, especially over areas that receive multiple snow squall bands. Up to 50 cm of snow is likely through the weekend for some regions.

Ontario Friday forecast conditions temperatures - Nov. 28, 2024

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Drivers are urged to plan ahead, and be prepared to adjust to the deteriorating conditions. Travel may quickly become hazardous due to sudden changes in the weather. Snow squalls can produce intense accumulating snow or near zero visibilities.

The powerful, multi-day event starts late Thursday

After the first blast of squalls off of Lake Superior Wednesday, even colder air, and stronger snow squalls are on the way this weekend. In fact, Friday will feature the coldest temperatures we've seen so far this season, helping to stir up the lake-effect snow machine.

Cold air is a key ingredient when it comes to lake-effect snow. The colder the air, the stronger the air and lake water temperature difference is, which leads to longer lasting, and more potent snow squalls.

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The multi-day lake-effect snow event will kick off late Thursday, intensifying and sticking around through Sunday.

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Persistent snow squalls will take aim at Cottage Country over the weekend, specifically from Kincardine to Dundalk, and Parry Sound to Barrie. While the squalls may meander a bit in intensity, their persistence will create whiteout conditions over the highways and near-zero visibility.

Ontario snow squall snow accumulation V2 - Nov. 28, 2024

Further north, Sault Ste. Marie will be caught in a hefty blast of lake-effect snow, joining the snowbelts in up to 30-50+ cm of snow. Peak snowfall rates could reach 5-10 centimetres per hour on Friday and Saturday.

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Environment and Climate Change Canada has issued snow squall warnings for these areas ahead of the event.

"Road closures are possible, especially over areas that receive multiple snow squall bands," the agency warns. "Prepare for quickly changing and deteriorating travel conditions."

Ontario snow squall precipitation forecast Friday pm - Nov. 28, 2024

While significant snowfall will certainly impact the traditional snowbelt regions, the snow could also reach into London, Guelph, and parts of the Greater Toronto Area (GTA) at times.

Additionally, forecasters are watching for the a chance for a long squall to impact Windsor, off of Lake Michigan, on Friday.

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Possible impacts to the GTA at times

Impacts to the GTA and Hwy. 401 will depend on a localized strong squall showing up at the right place, and the right time, which we cannot rule out. There's higher confidence in the snow forecast as you head north of Toronto, toward Kingston.

Meanwhile, areas including London, Guelph, Barrie, and sections of the 400, have multiple chances for a snow squall moving in, so it'll be important to remain weather-aware, and be prepared for the changing conditions.

Ontario snow squall precipitation forecast Saturday am - Nov. 28, 2024

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Anyone travelling to Buffalo or crossing the Thousand Islands Border Crossing for American Thanksgiving could be met with heavy, localized snow with 40-60 km/h winds leading to whiteouts, slippery conditions, and difficult winter travel.

While there will be some lulls in the lake-effect squalls, the bands will be rather persistent and meander across the snowbelts through the first week of December, and possibly well beyond, with more impressive snow totals likely.

Great for ski areas, but trouble on the roads

This is great news for Ontario's ski resorts, as early December will offer some of the best natural snow and snowmaking conditions we've seen in quite some time.

However, it does also mean trouble for the roads. Heavy localized snow with winds gusting between 40-60 km/h, will lead to whiteouts, slippery conditions, and difficult winter travel through this long duration and major lake-effect event.

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