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Many school buses were cancelled and even some schools were closed across Southern Ontario on Thursday as a high-impact snowstorm delivered widespread snowfall totals of 20 to 40 cm in some areas.

While the storm has begun to wind down heading into the evening, cleanup efforts are only just getting underway. With this amount of snow on the ground, it often takes more than a single night to fully dig out, especially on rural roads and backroads where plowing and treatment can take longer.

Because of this, we are expecting some lingering impacts for the Friday morning commute. The greatest concern lies across Eastern Ontario, where snowfall is only tapering off this evening. These areas will have significantly less time overnight to clear roads ahead of the morning bus run, increasing the likelihood of localized travel issues.

As a result, there is a chance that some school boards may opt for a second straight day of school bus cancellations on Friday. That said, this will be highly dependent on local road conditions and how effective overnight cleanup efforts are in each individual region.

Our highest confidence for additional cancellations is focused on the more rural zones within Tri-Board Student Transportation Services. This includes Central Hastings, North and Central Lennox and Addington, and North and Central Frontenac.

These areas rely heavily on rural bus routes that can remain snow-covered for longer periods following major storms. Because of this, we have assigned these regions a 75 percent chance of school bus cancellations on Friday.

Surrounding school boards with a heavy dependence on rural transportation are placed in the 50 percent category, where conditions could genuinely go either way. This includes areas covered by the Upper Canada District School Board, the Renfrew County District School Board, including the Renfrew and Madawaska regions, the remaining zones within Tri-Board, and Peterborough and Northumberland counties under the Kawartha Pine Ridge District School Board. In these regions, the final decision will likely come down to how quickly secondary roads can be cleared overnight.

For the Ottawa region, we have assigned a 25 percent chance. While Ottawa is more urban in nature and primary roads are expected to be in good shape by morning, the sheer volume of snow that fell may still present challenges on residential streets and bus routes. Whether that leads to cancellations remains uncertain.

A 25 percent chance has also been assigned to the Kawartha Lakes and Haliburton regions within the Trillium Lakelands District School Board, Clarington under the Kawartha Pine Ridge District School Board, and the northern portion of the Durham District School Board. These areas either lean more rural or did not see the most extreme snowfall totals from this storm. At this time, we are leaning toward buses running, but a few localized cancellations cannot be ruled out.

As you move farther west and north, confidence increases that roads will be in better shape by Friday morning. Snow tapered off earlier in the day in these areas, giving crews more time to clear routes. This includes a large portion of Southwestern Ontario as well as communities surrounding the Golden Horseshoe.

For these regions, we have gone with a widespread low to very low chance of school bus cancellations. No specific school board stands out as being particularly vulnerable, as outcomes will depend almost entirely on local road conditions. Boards covering more rural territory have been assigned closer to a 10 percent chance, while the more urban school boards across the Greater Toronto Area sit closer to 5 percent.

Across northern portions of Central Ontario, including areas covered by the Near North District School Board, the Rainbow District School Board and the Algoma District School Board, we have assigned a low 10 percent chance. Temperatures are expected to be very cold, but not cold enough to typically prompt cancellations on their own. Still, conditions are close enough to that threshold that a few isolated decisions cannot be completely ruled out.

Disclaimer: Instant Weather has zero authority when it comes to bus and school closures.

It is completely up to the school boards, bus companies, local authorities, and parents to decide what is best for their children. This is our best guess based on our forecast.