By Jessie Park, CBC News Ottawa, February 22, 2017
More potholes than usual have riddled Ottawa's streets this winter as the temperature continues to hover above and below the freezing point, according to the city's general manager of public works. Kevin Wylie says there have been 42 freeze-thaw cycles so far this winter compared to the average of 35.
Each of these cycles causes hundreds of potholes to open up throughout the colder months. When the weather warms up, water seeps into cracks in roads, which then freezes when the temperature drops, making asphalt break.
http://www.cbc.ca/news/canada/ottawa/more-potholes-ottawa-roads-2017-1.3992529