Freezing rain is one of the most damaging and frustrating aspects of a winter storm. Found at the front of a warm front cyclone, freezing rain is technically rain that freezes on contact with objects - anything from the ground to telephone and power lines can be affected. Besides the dangers for drivers and pedestrians from slipping, the weight of the ice often causes utility lines and tree linbs to sag and often break, taking out power, which many depend on for heat. The extra weight on roofs often causes leaks, encouraging homeowners to advance onto their roofs to break-up the ice, putting them in a very dangerous situation.   Freezing rain is caused when the atmosphere is warm enough for precipitation to fall as rain, yet the surface is cool enough to cause immediate freezing of the precipitation upon contact. A freezing rain warning will be issued if more than four hours of freezing rain are expected or if more than seven hours of freezing drizzle are expected.   Freezing rain is the culprit of some of the most devastating storms in Canadian history. Ice storms can be experienced anywhere in Canada except the North, but they are most common from Ontario to Newfoundland. The Ice Storm of 1998 was caused by six days of freezing rain, totalling 80 hours of freezing rain. Because of the population of the area affected, the damage was catastrophic. Twenty-five people were killed, many from hypothermia, while 100,000 others took safety in shelters.   While the storm of 1998 may be the most memorable, many other ice storms have hit Canada. Ontario and Quebec experienced 14 hours of freezing rain on Christmas Eve in 1986, leaving 25% of homes in Ottawa without power on Christmas Day. 200,000 people were left without electricity on the Avalon Peninsula when 15cm of freezing rain fell during the night of April 11, 1984. Freezing rain storms can come up suddenly. Above, a freezing rain storm came and went in the course of approximately two hours in January 2005 (Toronto, ON).