Four Types of Winter Precipitation
January 14, 2022
HASTINGS, Neb. (KSNB) - If you happened to step outside earlier this afternoon you may have noticed two or three different types of precipitation falling from the sky. But how can snow, sleet and rain fall at the same time? It all has to do with the temperature profile of the air above you. You may not have known this but most precipitation starts out as snow high up in the clouds. What happens to it after that depends solely on the temperatures found in the column of air it falls through.
If the column of air in the falls through is entirely warm, or in other words above freezing, it will melt into liquid water and fall to the ground as rain. But what happens if the column of air has a deep layer of warm air followed by a shallow layer at the surface that is below freezing? The frozen precipitation will melt and fall as rain to the ground. However, as it hits surfaces that are below freezing, it will refreeze, hence the term freezing rain. Then there is sleet. This type of precipitation starts off as snow, like the others, melts into rain as it travels through a shallow layer of warm air high in the column and then freezes before hitting the ground as it passes through a deep layer of cold air. It then lands on the ground as tiny ice pellets. And last, but not least, there is the precipitation that can gives us a white Christmas or travel headaches. Snow occurs when the entire column of air it falls through is below freezing. There are exceptions though. Snow can fall to the ground even if the temperature is above freezing right at the surface. Snow can fall to the ground at temperatures as high as 50 degrees. In most cases though in the northern United States, snow can be seen falling in temperatures at or below 40 degrees. It all depends on how deep the cold air is in the column the snow is falling through.
So the next time you see a wintry mix, you’ll “snow” why.
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