Why do roads crack in the winter?

It's all due to the freeze-thaw cycle. But what does that mean -- and how much does it cost Canadians?

Winter is here, and with it comes a familiar sight on Canadian streets and highways: cracked and damaged roads. But why does it happen every year?

The main culprit is the freeze-thaw cycle. During the day, snow and ice melt, seeping water into tiny cracks in the pavement.

At night, when temperatures dip below freezing, the water turns into ice, which expands and puts pressure on the pavement, widening the cracks.

When cars pass over those vulnerable spots, the damage gets worse and can lead to potholes. The cycle repeats throughout the winter.

CANVA - freeze-thaw cycle

The freeze-thaw cycle. (Cheryl Santa Maria/Canva)

And there's another culprit at play: Road salt. While it helps melt ice, it can also speed up the deterioration of the road.

There's a big price tag to all of this: A 2021 report by the Canadian Automobile Association says potholes cost Canadians an extra $3 billion a year in vehicle maintenance -- and municipalities budget hundreds of thousands, or even millions, of dollars each winter for city repairs.

Content continues below

Some cities, Like Thunder Bay, Ont., are experimenting with longer-lasting, more environmentally-friendly asphalts to protect roads before winter hits. But with more than a million kilometers of road across the country, it’s an ongoing challenge.

So you've hit a bump, and now your car has sustained damage

The best way to avoid damage to your car is to drive with caution, but sometimes, that won't be enough.

If you hit a pothole and your car becomes damage, do not exit your car unless you are a safe distance from oncoming traffic, Raymond Chan of CAA South Central Ontario told The Weather Network in 2020.

If you cannot operate your car, call for assistance. Some cities will cover pothole repairs, so don't forget to check the municipal website.

Editor's note: This article contains files from Emily Vukovic, former reporter at The Weather Network