With the recent snowfall, you probably already forgot about the icy patches that developed on the trees, grass, and most notably, the sidewalks; on Monday, January 25th! This was the result of a less common precipitation type know as freezing rain. You’re probably wondering what freezing rain is and why did we get it.
Freezing rain is rain that turns to ice immediately when it reaches the ground, trees, sidewalks, and other objects. Freezing rain forms when warm air tries to push out cold air, resulting in warm air being pushed above the cold air. So we have a situation where we have a cloud that is below freezing, a section of air underneath the cloud that is above freezing, and below freezing air at the ground. The formation process of freezing rain can be complicated, so let’s start in the cloud and work our way down to the ground. Freezing rain starts as a snowflake up in the clouds, which are below freezing. The snowflake then falls into a warm layer of air, which melts it into a raindrop. As this raindrop continues to fall, it encounters cold air when it nears the ground, but it doesn’t have time to freeze. Because of this, the raindrop freezes immediately when it hits the cold ground. This diagram from the National Weather Service clearly visualizes how this happens:
So as you can see, the conditions have to be just right for this to happen, making it less common. When the conditions are just perfect, freezing rain can become a huge deal, when there is enough freezing rain to create a thick layer of ice. When the ice becomes thick, it adds weight to the trees, powerlines, and any other objects. Sometimes, it even can cause trees and powerlines to break, like pictured below:
The photo above is a scene from an ice storm that moved through Arkansas and Kentucky in January of 2009, causing major tree and power line damage. According to The Weather Channel, 609,000 electric customers lost power in Kentucky as a result of this storm. This is just one of many examples of the damage freezing rain has done. We should all be happy the freezing rain we had on the 25th was only a minor event!