Potholes are caused by the freeze-thaw cycle that generally runs from mid-February to sometime in April. During the warm part of the day, the road surface thaws and run-off collects in the cracks in the pavement. When the temperature falls below freezing again, the ground and water re-freezes and naturally expands, which breaks up the pavement. Then traffic pops out these broken sections of pavement, creating potholes.
During pothole season, City maintenance crews repair these nuisances daily. Priority is given to the more heavily traveled roads, but all holes are repaired as detected. Unfortunately, with the cold patch materials used for repair and with the thawing and re-freezing conditions, a pothole can be repaired one day and need to be repaired again in a day or two. During the summer months crews use either a hot asphalt mix or velocity patching to repair potholes and large cracks in the pavement. Both of these methods produce a more permanent repair.
If you notice a dangerously large or deep pothole, please contact the Street Maintenance Department at 763-427-8254 so it can be taken care of as soon as possible.