MINNEAPOLIS — Our meteorologists talk a lot about dense, cold air, and the warm air riding over it, but what's the actual science behind how freezing rain happens?
Thanks to KARE 11's John Zeigler, the non-scientists among us now have a better idea.
According to Zeigler, it all starts with a cold air mass.
It's very cold and dense, so warm air starts to run into the cold air — or a warm front. That warm air rides up and goes over the cold air, forcing the warm air upward because, again, that cold air is dense. That's when the warm air actually starts to cool, and as it rises, it causes moisture.
That moisture then condenses, forming clouds. And when we have clouds, we can have precipitation.
Now, what happens to this precipitation with this warm air mass?
Say it's 35 degrees in the cloud — you'll have an actual water droplet, not a snowflake. The difference between sleet and freezing rain is small, but it's the depth of the warm layer and how long it's cold.
If there's more cold air in that column, the precipitation is going to be sleet. If it's just a tiny bit of cold air, it will be freezing rain.