Snow Day Predictor AbbotsfordWill school be cancelled tomorrow in Abbotsford?

Enter your Abbotsford postal code or "Abbotsford, British Columbia" into the predictor above. Abbotsford School District #34 is one of the more closure-prone districts in the Lower Mainland because of its position in the Fraser Valley arctic outflow corridor and the long rural bus routes across Sumas Prairie. The official call is typically announced by 6:00 am on the district website (abbyschools.ca) and through local radio. Our forecast gives you an advance probability the night before based on the overnight outflow strength and precipitation type.

Abbotsford sits at the mouth of the Fraser Canyon, which is the most direct path for arctic air to drain from the British Columbia interior plateau to the coast. When an arctic high builds over the interior, the pressure gradient drives dense cold air through the canyon and out across the eastern Fraser Valley, with Abbotsford receiving the most direct outflow. Vancouver, 75 km west, is sheltered by the orientation of the valley and the moderating influence of the open Strait of Georgia. Temperature differences of 5 to 10 degrees between the two cities are normal during outflow events.

Arctic outflow is a gap wind phenomenon. Cold dense air pools over the interior plateau under a winter high-pressure system, and that air drains down through the lowest passes in the Coast Mountains toward the warmer coast. The Fraser Canyon is the largest and lowest such pass in southwestern British Columbia, so most of the cold-air drainage funnels through it and emerges directly over Abbotsford and Chilliwack. The outflow can persist for days at a time and is responsible for the heaviest snowfalls and coldest temperatures in the Lower Mainland.

Mission School District (SD #75) and Chilliwack School District (SD #33) almost always close in tandem with Abbotsford SD #34 because all three districts sit in the same Fraser Valley arctic outflow corridor and face the same morning road conditions. If our forecast shows a high closure probability for Abbotsford, the probability for Mission and Chilliwack is typically equal or higher. Each district announces independently, with Chilliwack usually the last to call because outflow conditions are most severe further east.

The November 14 to 16, 2021 atmospheric river dropped roughly 250 mm of rain on the eastern Fraser Valley in 48 hours, overwhelming the Barrowtown pump station and re-flooding the historic bed of Sumas Lake. SD #34 closed several schools on Sumas Prairie for weeks, with displaced students bussed to alternative buildings while pump stations were repaired and roads were re-engineered. The event is the benchmark for combined atmospheric river and flooding risk in the city, and it changed how the district plans for compound winter weather events.

Abbotsford receives more than double the annual snowfall of Vancouver International Airport and roughly 50 percent more than Surrey. The reason is geographic: Abbotsford sits at the eastern end of the Fraser Valley in the direct path of arctic outflow from the interior, while Vancouver and Surrey are further west and partially sheltered. A storm that delivers 2 to 5 cm of slush to Vancouver routinely drops 20 to 30 cm of dry snow on Abbotsford. SD #34 closure rates reflect this difference, with Abbotsford closing several times in most winters while Vancouver-area districts close at most once or twice.

Sumas Prairie is the reclaimed bed of historic Sumas Lake, drained in the 1920s and now covered by dairy farms, blueberry fields, and several SD #34 schools. The prairie sits below sea level in places and forms a natural frost hollow, with overnight temperatures regularly 3 to 5 degrees colder than the rest of Abbotsford. Bus routes across the prairie are among the first to be cancelled when ice fog or drifting snow makes them unsafe, and the November 2021 flooding showed how vulnerable the prairie schools are to compound winter weather events.