Kristen's Classroom: Wintry mix and donuts
AUSTIN (KXAN) - Some winter storms seem to throw the kitchen sink at us when it comes to precipitation type - rain, snow, freezing, sleet, etc. Rain and snow are easily understood but what about the others?
Freezing rain
Precipitation type largely depends of the vertical temperature profile of the atmosphere. Freezing rain hinges on the presence of below freezing temperatures near the surface. If a raindrop falls from the cloud and encounters this layer of freezing air, it will freeze on anything and everything.
Freezing rain is responsible for the historic ice storm that crippled the city of Austin in 2023.
Sleet
Similar to freezing rain, this type of precipitation is dependent on the temperature profile between the cloud and surface, but also needs a little help from up above.
Sleet (and snow, for that matter) both need saturation in the dendritic growth zone, or more commonly known as the "snow growth zone". This allows for ice crystals to initialize. If not enough moisture, no ice crystal will form.
If an ice crystal forms and falls out of the cloud, encountering a brief layer of air above freezing before falling through a deeper layer of subfreezing air, the result is a sleet pellet. Think of this as a partially melted snowflake.
How to distinguish wintry precipitation
A fun way to think of wintry precipitation is using donuts. If you leave a donut outside and it appears soggy, there's a good chance you're just experiencing plain ol' liquid rain. If that donut looks like it has a glaze on it, that would be an indicator of freezing rain. A donut coated in sugar? That would be sleet. And a donut with coconut flakes would indicate the presence of snowflakes.