What is Sleet?
Sleet is wintry precipitation, and its exact definition depends on where you are. In Europe, sleet refers to snow that has partially melted on its way to the ground. In the United States, this is called slush or wet snow. Sleet, to meteorologists in the United States, consists of frozen raindrops that hit the surface as little ice pellets.
In climes where snow is not as common, such as the Southeastern United States, a lot of sleet, in any form, is bad news. People can drive through snow, but not on ice. Sleet is nearly always accompanied by freezing rain in these kinds of weather systems and goes on the pavement as an icy glaze.
One reason the Southeast and similar climates have a problem with sleet is because of air temperatures. A weather system that dumps snow in the Midwest does so because the air temperature is below freezing, through all the layers of the system. This is not necessarily the case in the South, where winter temperatures are often about 35°F (1.67°C) at the surface. There are several layers of warm and cold air, so any snow or rain that falls has a chance to melt, re-freeze and melt several times on its way to the ground. The South most often receives snow when a cold air mass precedes the precipitation by a day or two. When the cold air and the storm system arrive at about the same time, freezing rain and sleet are the usual result.
Sleet and freezing rain are also the two components of the ice storm. Snow may slow things down, but ice is destructive. It coats tree limbs and power lines, making them sag and break. Ice causes widespread power outages and structure damage from falling tree limbs.
Sleet is different from hail, in that sleet is seen exclusively in the winter months. It is a product of a winter storm system. Hail, on the other hand, may fall any time during the year. It is associated with severe thunderstorms and tornadoes.
Hail is always formed in cumulonimbus thunderclouds. While a severe thunderstorm may not produce hail, hail is always an indicator of severe weather. Sleet is an indicator of both cold and warm air aloft in a winter storm system.
The best way to deal with sleet after it falls is to stay inside if possible. Ice is treacherous and can easily cause falls or other accidents. Have some emergency supplies available if the power goes out, and try to stay indoors.
Written by A Kaminsky
