A Colorado low pushes a major winter storm into southern Ontario Wednesday through Thursday, bringing with it dangerous accumulations of ice and snow that will severely affect travel conditions and power lines. Expect multiple commute times to be affected.
“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 impacted for over 20 hours, with dangerous winter travel expected for Wednesday evening, Thursday morning and even Thursday evening commutes.”
Prolonged risk of freezing rain leads to widespread warnings
The bull’s-eye for the heaviest freezing rain will be in southwestern Ontario – from Windsor to London to the Niagara Peninsula. One of the most treacherous roads will be Highway 3, north of Lake Erie and along parts of the 401.
Starting Wednesday evening, precipitation rates are expected to increase into the night hours and continue well into Thursday morning.
Due to the prolonged duration of this event, the region is on widespread freezing rain warnings.
The amount of ice accumulation depends on surface temperature, wind speeds and precipitation rates. One thing to note when looking at the ice forecast is that only about half of the falling ice rain will accumulate on surfaces like roads, tree branches, and power lines.
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With wind gusts in excess of 40mph, the risk of tree and power line damage is widespread, with prolonged power outages looming through Thursday.
Threat of ice pellets and heavy snow
For the Greater Toronto Area (GTA) and the north and east regions, more cold air flows in from the north. This creates a much shallower melt layer, leading to accumulations of snow and ice pellets.
Between 5 and 15 inches of snow is expected to trigger the winter storm event through Wednesday evening’s commute. Then the snow will quickly turn into copious amounts of ice pellets, probably the most since April 2018.
Ice pellets don’t accumulate as easily as snowfall. They will still blow around and create smooth surfaces, but the impact will be less than Freezing Rain. Don’t be fooled, however, as ice pellets are very heavy, making them difficult to shovel.
There will be a significant amount of ice pellets stuck between snow and freezing rain. In some areas of the GTA, more than 10 hours and 5-10 cm accumulation of ice pellets can be seen.
While ice accumulation will be minimal, widespread winter storm warnings have been issued for the GTA and surrounding areas to the north due to the mix of snow and ice.
There will be additional freezing rain on Thursday, giving travelers and commuters another headache.
WATCH: Expect travel delays as a significant ice storm watches southern Ontario
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Stretching from the shores of Lake Huron to Kingston and stretching across eastern Ontario, there is a higher chance of seeing over 20 inches of snowfall through Thursday.
Amounts are beginning to fall the further northeast you travel, but even the Ottawa region expects more than 20cm of snowfall at this low as the region remains on the cold side of this storm, prompting snowfall warnings to be issued.
The system is scheduled to depart Thursday evening and leave the region on Friday.
Visit The Weather Network for more updates and information on this Ontario winter storm. Information on contingency plans and kits is available at http://www.getprepared.gc.ca.
