SIOUX CITY, Iowa (KCAU) – For Wednesday’s edition of Classroom 9, I will explain what the four main types of precipitation are and how they’re formed.
In Siouxland, we see every type of precipitation and sometimes a mix of all of them! But do you know how each of them are formed?
There are four primary types of precipitation and they’re all dependent on the temperature of the column of air which extends from the base of the cloud to the ground.
First, there’s rain, which is the most simple of all the precipitation types.
The temperature throughout almost or the whole column of air is above the freezing mark of 32°, so the raindrop falls out of the cloud and hits the ground as liquid water.
Freezing rain is similar in that there’s a large portion of the pathway between the cloud and the ground is above freezing.
However, near the surface, the temperature drops below freezing and the water becomes what we call “supercooled,” meaning that the temperature of the water has actually fallen below 32°!
When the freezing raindrop hits any surface, whether it be the pavement or tree branches, the rain immediately snaps into ice.
Freezing rain is among the most hazardous of all the precipitation types, especially when it comes to winter weather driving and the slippery surfaces it creates.
Sleet is similar to freezing rain but the warmer-than-freezing layer in the column is shallower, which means the precipitation has a chance to refreeze before falling to the ground as sleet pellets.
Finally, there’s snow!
Snow happens when the entire column of air from the base of the cloud to the ground is below the freezing mark.
During the wintertime, there’s generally less moisture available in the air than during the other seasons because colder air has a lower capacity for water.
A snowflake comes together with lots of tiny ice crystals that stick together in the cloud and then float down to the ground.
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