Freezing rain is the rain that falls when the surface temperatures are below freezing, they do not freeze the air but rather freeze the instant they strike an object such as a road or car. Unlike sleet, a mixture of rain and snow, ice pellets or hail freezing rain is made entirely of liquid droplets. The raindrops become supercool while passing through a sub-freezing layer of the air hundreds of meters above the ground, and then freeze upon impact with any surface they encounter including the ground, trees, electrical wires, and automobiles this result in the ice called glaze which can accumulate to a thickness of several centimeters and cover all exposed surfaces.
What is sleet?
Sleet and freezing rain both occur by the same general process. Sleet refers to a mixture of snow and rain as well as raindrops that freeze on their way down. Unlike snow, the raindrops pass through a liquid form before freezing. The result is that they are not light and fluffy. Sleet is a regionally variant term for two distinct forms of precipitation. The Rain and snow mixed, snow that partially melts as it falls Ice pellets, one of three forms of precipitation in wintry mixes, the other two being snow and freezing rain. Liquid raindrops in a layer of warm air well above the surface fall into a layer of freezing air hugging the ground. The difference between these two wintry precipitation types depends on the thickness of the layer of freezing air.
How does freezing rain forms?
Freezing rain can occur in two different areas of a cyclone, as seen in the graphic below. The most common area is to the north of a warm front. As the warm air lifts over the front, it condenses, and precipitation begins to develop. Occasionally, freezing rain can develop behind a cold front as moist air is forced over the cold air. This scenario is not as typical as the former, however, when freezing rain develops in this fashion, it’s usually very light.
Hydrometeors – Water and Ice
r Rain (drops of water >0.5mm diameter)
rx Freezing Rain (i.e. rain which freezes on contact with the ground and vegetation)
d Drizzle (drops of water <0.5mm diameter
Facts about freezing rain:
- Ice is winter’s silent hazard.
- Freezing rain is dangerous.
- Freezing rain is actually melted snowflakes.
- All that ice is extremely heavy.
- Sleet is freezing rain’s annoying cousin.
- Sleet is like snow with an ugly secret.
- When a storm’s coming, join the bread and milk lines.