Potholes and sinkholes: Uncovering the hidden dangers beneath our roads
Potholes vs. Sinkholes: What's the difference?
They can both swallow your tire, or even your car, but potholes and sinkholes are not the same things.
Allow us to explain.
One is a surface problem; the other starts deep underground.
Potholes are all about weather and wear, and in Canada, they peak in late winter and spring.
RELATED: Crews rescue boy swallowed up by sinkhole in Thompson, Man.
Here’s the science: Water seeps into tiny cracks in the road. When temperatures drop below freezing, that water expands as ice, forcing the pavement apart.
The freeze-thaw cycle can wreak havoc on our roads, causing more potholes to form. (Graphic: Canva/The Weather Network)
Then, when it melts, it leaves behind gaps and weak spots.
Add the weight of passing cars, and eventually, the surface collapses.
Sinkholes, meanwhile, are completely different—they start below the ground.
Sinkholes can emerge with little-to-no warning. (Image: UNO Public Safety)
Over time, slightly acidic rainwater seeps underground, either dissolving rock (like limestone) below the surface or washing away soil. That creates a hidden void beneath the surface. And even if the surface looks untouched, over time that space continues to grow, out of sight.
Eventually, the ground above can’t support itself and collapses, sometimes without warning.
Sinkholes are driven by geology and water underground, not just the weather at the surface.
Main differences between potholes and sinkholes
The main differences are that potholes form from the top down and sinkholes collapse from the bottom up.
A pothole is like the dings and scrapes in an old hardwood floor. It may feel weathered and bumpy, but for the most part it's still structurally sound. With sinkholes, it's like the boards holding up your floor have been infested with termites—eating away at the wood until there's little left beneath the surface.
Lastly, and perhaps most importantly, potholes are annoying and costly, damaging tires and suspensions. Sinkholes can be dangerous and destructive, swallowing roads, cars, and even buildings.