Houses 'crack' in Canadian cold spell. 20/01/2005. ABC News Online

ABC News Online: "Houses 'crack' in Canadian cold spell A cold spell gripping the Canadian capital of Ottawa is so intense that houses have started to produce loud cracking noises, prompting people to report burglaries and gunfire. A spokeswoman said police received about 20 calls when the temperatures dipped to minus 40 degrees Celsius, excessively cold even by Ottawa's standards. The calls were about gunshots, breaking and entering, and people making noise. Police responded to each call but found nothing amiss. They concluded that one possible reason for the loud cracking noises were nails popping in the sub-zero temperatures. -Reuters/ABC"