Gonz said:
Here's a unique opportunity. I can seriously ask a Canuck a question that (so far) no American has been able to answer.
It seems I was taught that moving water won't fereze. So, WTF?
Rocks on the bottom of the river + extremes of cold. The rocks will slow the water somewhat at it's base...extreme colds means that the slowed water will freeze and build up. The obstruction will get larger and block more water, which will freeze and worsten the flow.
Imagine this if you will. When something is freezing, it's molecules are slowing down until they come to a stop (frozen or solid state), they're losing energy. You can slow down the process by mechanically adding energy to the molecules (stirring the water, having it flow downstream)...often indefinatly.
At some point, when it gets cold enough...you are losing more energy from the cold outside than you are getting back from the friction against either the river bottom or sides or the sides of the glass *if you're stirring it* and the water loses all of it's heat/energy and freezes.
That's the physics of it...in laymen's terms....it's just that fuckin' cold innit?