Why winter storms are becoming bigger and badder around the Great Lakes — and what it means for those at risk

CBC's Great Lakes Climate Change Project is a joint initiative between CBC's Ontario stations to explore climate change from a provincial lens. Darius Mahdavi, a scientist with a degree in conservation biology and immunology and a minor in environmental biology from the University of Toronto, explains how issues related to climate change affect people across the province, and explores solutions, especially in smaller cities and communities.

This Christmas, as a winter storm blanketed southern Ontario, Gabe Oni hunkered down at the Hamilton warming centre The Hub along with dozens of other vulnerable and unhoused people who were left with nowhere to stay.

"It was insane," Oni said. "The snow came out of nowhere and so nobody was really, like, prepared for it. Usually everyone prepares during the year or whatever, prepares whatever they have to prepare. But nobody was ready. There were like no jackets … It was bad."

Jen Bonner, The Hub's executive director, said the wind and blowing snow knocked over tents and forced people to seek shelter. For anyone without a home, a winter storm can be deadly, she said. 

"A tent can collapse very easily with a significant amount of snow. A tent can collapse when winds are up really high. People are sleeping in there, and so if they are in a very deep sleep, people could get buried alive in their own possessions." 

Service providers across Ontario struggled as the snowstorm forced them to adapt.

And unfortunately, due to climate change, these types of scenarios are likely to become more common around the Great Lakes over the next several decades.

Another Ontario region hit hard during the recent holiday storms was Chatham-Kent, just northeast of Windsor. Heavy snowfall and extreme winds buried cars and generated whiteout conditions, preventing employees, volunteers and service users from reaching Chatham's Hope Haven, a warming centre that stays open overnight in extreme cold. 

"We were anticipating cold temperatures, but the wind and the accumulation of snow that happens over the course of a winter or over the course of a week … we got that over the course of a few hours," said Loree Bailey, director of Hope Haven.

"When people are living in encampments, they have a lot of their belongings with them, all of their worldly and necessary possessions on them. And they are now trudging through that weather." 

The storm that hit Ontario in December was driven by a number of weather events, but a major contributor to the heavy snowfall was what's known as the "lake effect."

The lake effect is a relatively rare phenomenon that can only occur in a few places around the world with large enough bodies of water, including the Great Lakes. 

The Great Lakes, which hold over 20 per cent of the world's freshwater, are particularly prone to lake effect storms — as those who live in communities on the shoreline will tell you. 

A lake effect snowstorm occurs only under particular conditions, when cold air passes over a relatively warm body of water. The air picks up moisture and heat from the lake, which causes the newly warmed air to rise. High in the atmosphere, the moisture then cools and condenses, and starts to fall as snow.