Key Takeaways
- Snow squall activity is expected to intensify off Lake Huron and Georgian Bay, affecting several counties in Southern Ontario
- School bus cancellations are likely in the hardest hit regions, with a 90% chance in the southern portion of the Bluewater District School Board and the entire Avon Maitland District School Board
- Road closures and school closures are possible due to heavy snowfall rates and strong winds causing blowing snow and localized blizzard conditions
- The probability of school bus cancellations drops off quickly outside the primary snow squall corridor, with a 50% chance in some regions and less than 25% in others
Introduction to Snow Squall Activity
Snow squall activity has been developing off Lake Huron and Georgian Bay throughout the day on Thursday and is only expected to intensify as we head into the overnight and early morning hours of Friday. These snow squalls are forecast to become nearly stationary, affecting much of Grey and Bruce counties, Huron County, Perth County, Wellington County, Simcoe County, and parts of the northern Greater Toronto Area. The heavy snowfall rates and strong winds causing blowing snow and localized blizzard conditions will likely lead to hazardous travel conditions, making it difficult for school buses to operate safely.
Impact on School Bus Cancellations
With snowfall rates reaching 5 to 10 cm per hour in the heaviest bands, it is almost certain that school buses will be cancelled in the hardest hit regions on Friday. School closures are also possible as numerous road closures are expected overnight, with conditions continuing to worsen. The southern portion of the Bluewater District School Board and the entire Avon Maitland District School Board are positioned to face the full impact of the long-lasting snow squalls through Friday morning, making it extremely unlikely that buses will be able to operate safely, especially across rural roads. As a result, these regions have been assigned a 90% chance of school bus cancellations.
Regional Breakdown of Snow Squall Impact
Outside of these zones, there is also a high chance of cancellations along the southeastern shoreline of Georgian Bay. This includes the Simcoe County District School Board (west and central areas), the northern section of the Bluewater District School Board, Wellington County under the Upper Grand District School Board, and the Thames Valley District School Board’s Oxford and Middlesex regions. While confidence is high, there remains a chance that a few of these regions might attempt to run buses either because they sit just outside the core impact zone or because the school board typically has a higher threshold for cancellations. As a result, these regions have been assigned a 75% chance of school bus cancellations.
Probability of Cancellations in Other Regions
The probability of school bus cancellations drops off quickly outside the primary snow squall corridor. The Simcoe County District School Board’s north and south areas, the Bruce Peninsula, Dufferin County, Waterloo Region under the Waterloo Region District School Board, and the London area under the Thames Valley District School Board have been assigned a 50% chance of cancellations. In these regions, it could go either way and will largely depend on the exact positioning of the squalls. For Kitchener and London specifically, both are more urban school boards with a higher threshold for cancellations, which may reduce the likelihood of cancellations.
Lower Probability of Cancellations in Other Areas
There are also regions with a lower probability of school bus cancellations. Elgin County under the Thames Valley District School Board, the Grand Erie District School Board, York Region under the York Region District School Board, the northern portion of the Durham District School Board, and the southern section of the Trillium Lakelands District School Board, including the southern City of Kawartha Lakes, have been assigned a 25% chance of cancellations. While we do not expect widespread cancellations in these regions, if the squalls push far enough inland and produce pockets of whiteout conditions, there is still room for some surprises. Elsewhere across Southern Ontario, there is less than a 25% chance of a snow day, as the snow squall activity is not expected to have a significant impact on these areas.
Conclusion
In conclusion, the snow squall activity off Lake Huron and Georgian Bay is expected to have a significant impact on school bus cancellations in several counties in Southern Ontario. While there is a high chance of cancellations in some regions, the probability drops off quickly outside the primary snow squall corridor. It is essential for parents and students to stay informed about the latest weather forecast and school cancellation announcements to plan accordingly. By understanding the regional breakdown of the snow squall impact and the probability of cancellations, individuals can make informed decisions and stay safe during this winter weather event.