If you have done it yet, get it winterized on Sunday. Check the clear plastic water strainer on the input side of the pump, its quite vulnerable.
I know -7C is not cold for some people in Ontario, saw 3 people in shorts and sweat shirts at Costco (Barrie), including one in shorts and shirt pumping gas, standing in 6" of snow.
Water does freeze at 0C and with the forecast its not likely to melt for a while, only get worse. You may have to figure a way to get heat to the pump etc, to get the job done, or expect big repairs next spring.
Ken