The type of precipitation that falls with a winter storm often depends upon the storm's path. Since cold air is usually found on the north side of a storm and milder air on the south side, wintry precipitation generally falls in areas north of the track of the storm's center. Freezing Rain Freezing rain is caused by rain droplets that freeze on contact with the ground or objects near the ground, leaving a frozen glaze. The temperature of the ground must be below freezing, and the rain droplets must exist in a liquid state at temperatures below freezing for freezing rain to occur.
Freezing rain can glaze roadways with ice causing extremely hazardous driving conditions.
Bridges and overpasses typically freeze more quickly than other surfaces and are particularly dangerous. Sleet Sleet falls to earth as ice pellets. These ice pellets are formed as snowflakes melt into raindrops as they pass through a thin layer of above-freezing air. The rain drops than refreeze into particles of ice as they pass through a sub-freezing layer of air near the ground. Snow Snow is frozen precipitation in the form of six-side crystals.