Some of the ice on the sidewalk and lower driveway had loosened its attachment though it was -12°C this afternoon. Prying up with my flat spade it felt like a backhoe lifting up slabs of old sidewalk. The ice was 5 to 8 cm thick in places. In other places I used my metre long crow bar to crack the ice. Eventually I had to stop: my feet were getting cold and my wrists were objecting to the pounding.