A winter of fluctuating temperatures is making for some pretty nasty potholes in Toronto.

Fifty crews were dispatched today to get a jump on road repair after the weekend's thaw created ideal conditions for potholes.

The City of Toronto has filled 4,000 potholes so far this year, compared to about 1,500 by this time last year.

But the repair blitz doesn’t mean less damage.

Tire repair companies are reporting lots of calls from drivers affected by the road conditions -- some workers going from one pothole-related incident to the next.

Crews say they’ll continue to do what they can and the City of Toronto is encouraging people to report any holes they see by calling 311 or online.

Winter potholes are often caused by water getting trapped in hairline cracks in the asphalt. As water freezes and thaws -- and subsequently expands and contracts -- the cracks grow and break apart the roads.