Snow squalls batter London region, bringing closed roads, schools, and flight disruptions

Emergency crews across southwestern Ontario kept busy on Thursday, responding to dozens of collisions, as a steady stream of snow squalls blanketed the region with as much as 30 centimetres of snow, prompting widespread school closures.

Heavy snow that began Wednesday night continued through the day Thursday before easing up in the afternoon, resulting in yellow snow squall warnings to be dropped for most areas.

Some lake effect snow bands continued into the early evening, impacting areas largely northwest of London into southern Huron County, where a snow squall warning remained as of 6:30 p.m.

In Toronto, upwards of 22 centimetres of snow was recorded from the same storm system, leading most flights at Pearson Airport to be cancelled or severely delayed. Several Air Canada flights between London and Toronto were cancelled, as was a WestJet flight to Calgary.

"By this morning, we had some stations that reported 20 centimetres, locally up to 30 centimetres ... especially for areas west of London," said Eric Tomlinson, a meteorologist with Environment Canada, adding that they were preliminary estimates.

"For areas west of London, we had north winds throughout the event, and so embedded within the bigger system, there was some lake enhancement just south of Lake Huron. For areas just west of London, towards Strathroy, that's where we saw some of those higher amounts."

Areas east of London toward Woodstock recorded preliminary snowfall amounts of 10 to 15 centimetres, he said. More concrete numbers are expected Friday.

Another two centimetres is expected to fall throughout Friday in London, with another two to four centimetres Friday evening, according to Environment Canada's short-term forecast.

The Middlesex-London Health Unit extended an extreme cold alert it issued on Wednesday until Friday. Temperatures into Friday morning are expected to hit a low of -17 C in London, feeling like -24 C.

"The daily highs, at least for this weekend, we'll be closer to zero — to minus three, minus two," Tomlinson said. "Heading into next week, we could see daily highs much closer to minus six, potentially on certain days, down to minus 10."

Ontario Provincial Police say their Thursday was spent tending to a string of weather-related collisions and incidents across southwestern Ontario.

Multiple closures were reported through the day along local 400-series highways, with most cleared by 4 p.m. A westbound closure of Hwy. 401 in Chatham-Kent that began in the morning continued into the evening. Information about possible injuries was not immediately available.

Those were among at least 217 collisions provincial police say they responded to between 9 p.m. Wednesday and 4 p.m. Thursday across West Region, which covers an area stretching from Windsor east toward Brantford, and north to the Bruce Peninsula.

A number of crashes involved vehicles ending up in the ditch.