A memorable and violent winter storm is approaching southern Ontario, with heavy snowfall and significant ice formation expected to severely impact travel and power lines. Ontario residents are often affected by Colorado lows, but this one in particular has particularly worried forecasters.
“Its easterly course over the Great Lakes, coupled with the Gulf’s humidity and a winter-spring temperature battle, provide all the conditions ripe for prolonged, frigid precipitation,” warns Rachel Modestino, meteorologist at The Weather Network. “Some regions may be affected longer 20 hourswith dangerous winter travel expected for Wednesday evening and Thursday morning drives.
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Southwestern Ontario: Dangerous and persistent freezing rain threat
The bull’s eye for the heaviest freezing rain will be in Southwestern Ontario, including Sarnia, London and Hamilton, as well as Niagara and South. This is as if the Colorado Low Noses lie in a melt layer 1-2 km above the surface – a layer just thick enough to melt falling snow but then freezes on contact with sub-freezing ground lies.
Starting Wednesday evening, precipitation rates are expected to increase into the night hours and continue well into Thursday morning.
“These regions can experience one [more than] 20-hour ice storm,” says Modestino. “Thursday morning commuters across the Niagara Peninsula should avoid unnecessary travel.”
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Widespread winter storm watches and special weather forecasts apply for the continued duration of the freezing rain.
The amount of ice accumulation will be difficult to measure given the varying rates of precipitation. Regardless, the amounts are expected to involve dangerous travel and slick conditions.
With wind gusts in excess of 50mph, tree and power line damage are also common, with the risk of possible outages through Thursday.
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Greater Toronto Area: Ice pellet and heavy snow threat
For the Greater Toronto Area (GTA) and the north and east regions, there is a little more cold air inflow from the north. This creates a shallower melting layer, resulting in snow and ice pellets.
Between 5 and 15 inches of snow is expected to trigger Wednesday night’s winter storm event while commuting through the region. A transition from snow to ice pellets is expected during the nighttime hours.
Ice pellets don’t accumulate as easily as snowfall; They will still blow around and create slick surfaces, but much less dangerous than freezing rain. Don’t be fooled though, ice pellets are very heavy which makes shoveling difficult.
There will be a significant amount of ice pellets stuck between snow and freezing rain. More than 10 hours of ice pellets can be the dominant type of precipitation in some areas throughout the GTA.
Forecasters are also monitoring the risk of efficient freezing rain and icing on Thursday when the system begins departure.
From the shores of Lake Huron and Cottage County, which stretch across eastern Ontario, there is a higher chance of seeing over 20 inches of snowfall through Thursday.
Amounts are starting to fall the closer you travel to Quebec, but even the Ottawa region expects 15-20cm of snowfall at this low as the region stays on the cold side of this storm.
The system is expected to shut down Thursday evening and leave the region on Friday.
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Stay tuned to The Weather Network for more forecast updates for Ontario. Information on contingency plans and kits is available at http://www.getprepared.gc.ca.
