Heavy snow and recent thaw were the perfect recipe for pothole pain.

Roads have held up well this year, but melting snow might change that

Potholes have been no big deal this winter, but mountains of melting snow should soon bring a change for the worse.

It’s amazing how quickly most of the snow dumped on us last week vanished, after several days of balmy weather to counter the record-cold temperatures of just a few days earlier, before quickly returning with more nasty weather Wednesday.

We’ll soon pay for our brief opportunity to bask in the glorious warmth, as moisture from melting snow seeped into the pavement, creating ideal conditions for potholes to get started.

When melt-water penetrates the road surface and freezes as temperatures return to wintry, it expands and loosens the asphalt. And as vehicles pass over the asphalt, it cracks and crumbles, allowing potholes to form. We haven’t had much snow this winter until the enormous dump last week, confirmed by figures provided by Toronto transportation services that show a startling difference between this year and 2018.

City patching crews filled about 9,000 potholes between Jan. 1 and Feb. 1, said road operations superintendent Mark Mills, compared to 41,700 in the same period in 2018.

“Last year we had a lot of freeze-and-thaw events” that degraded the road surface, Mills said, adding, “we think we’ll see a big increase,” in potholes in the next couple of weeks, due to the sudden melting of so much snow.

The winter of 2018 was excep- tionally bad for potholes, with far more patched during early February than in the previous several winters, according to numbers compiled by the city.

With little snow and consistent temperatures this winter, the city was able to send out about 25 patching crews on most days, Mills said, and they were able to keep up with potholes as they sprouted in the road.

All that changed last week, when the same city workers were redeployed to snow clearing, allowing some potholes to remain unfilled while the melting snow creates the conditions for lots of new ones, Mills said. So far, “we have not seen a big increase in 311(pothole) calls. In fact, it’s a lot less than last year.”

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