Sarah Bauer woke up to a shaking house.
She thought maybe an earthquake had struck near her home in Torrance, a village in Ontario’s cottage country.
But when she looked outside, she saw a massive tree had collapsed onto her driveway under the weight of rapidly accumulating snowfall, taking down a power line with it.
“It was freaky,” she said.
The storm that hit parts of central Ontario in late November and early December was the biggest in recent memory, meteorologists said, reportedly dumping a 140 centimetres on Gravenhurst, a town just south of Torrance.
Another round of intense lake-effect snow hit areas off Lake Huron again this week, with further squalls expected into the weekend.
Areas off the Great Lakes are used to big snowfall events, earning the title of Ontario’s snowbelt.
Yet something new is happening. Climate scientists and meteorologists say climate change, driven by the burning of fossil fuels, is helping create conditions that can strengthen the storms.
Richard Rood, a climate scientist who studies the Great Lakes, says lake-effect snowstorms will likely intensify as the planet warms.
“They’re probably better interpreted as typical of the future rather than extreme compared to the past,” said Rood, professor emeritus of climate and space sciences at the University of Michigan in Ann Arbor.
Lake-effect snow relies on a combination of an outbreak of Arctic cold air and the comparatively warmer water of the Great Lakes. As the air passes over the lake, it picks up moisture and dumps it on communities downwind, in snowfall events often characterized by intense and localized squalls.
Those storms are typical in late autumn or early winter, when lake temperatures are still relatively warm. By the depths of winter, ice cover helps to cut off evaporation, said meteorologist Arnold Ashton.
“Typically, you don’t get it quite as often in January, February — certainly in February — because you have more ice on the lake,” said Ashton, a senior meteorologist with Environment Canada.
But the warmer the lakes get, the more heat and moisture there is for those blasts of Arctic air to pick up, intensifying snowfall. And as warmer winters limit the amount of ice cover, those storms may stretch deeper into the season.
“The Gravenhurst apocalyptic metre-and-a-half of snow was a late November, early December event … but with a warming climate, those events could linger,” Ashton said.
Gravenhurst was under a local state of emergency for more than two weeks as crews cleared snowed-in roads and tried to restore power to tens of thousands of customers. Stranded drivers had to be rescued from a highway that stayed partially closed for nearly three days.
