I'm in southern Ontario as well. Last night it went down to -21c before windchill. It has been colder though, the river behind my house is still flowing fine. It has to be -20c consistently before it freezes over, tomorrow it warms up to -3. Still -11c with windchill, but I'm taking the kids out tobogganing on the trails. It's beautiful with the sun out.
Last time the river froze over (briefly) was 2 years ago
http://www.youtube.com/watch?v=ZybGVq-G0OA
The last good persistent freeze was in 2009, resulting in big blocks of ice on the trails when the thaw sets in.
Doubtful if that will happen. Although conditions might be right for a quick melt and flood followed by another flash freeze if the temperature continues swinging up and down like it has. That leads the best picture opportunities :)







