Freezing rain
Freezing rain often causes major power outages by forming glaze ice. When the freezing rain or drizzle is light and not prolonged, the ice formed is thin and usually causes only minor damage (relieving trees of their dead branches, etc.). When large quantities accumulate, however, it is one of the most dangerous types of winter hazard. When the ice layer exceeds approximately , tree limbs with branches heavily coated in ice can break off under the enormous weight and fall onto power lines. Windy conditions and lightning, when present, will exacerbate the damage. Power lines coated with ice become extremely heavy, causing support poles, insulators and lines to break. The ice that forms on roadways makes vehicle travel dangerous. Unlike snow, wet ice provides almost no traction, and vehicles will slide even on gentle slopes. Because freezing rain does not hit the ground as an ice pellet (called "sleet") but still as a rain droplet, it conforms to the shape of the ground, or object such as a tree branch or car. This makes one thick layer of ice, often called "glaze".