Graupel in Decatur

While most of Tuesday’s precipitation fell in the form of snow, there was another precipitation type in the mix – graupel.

While on the job as an Earth Science teacher at Bellmont High School, Jennifer Douglas reported hearing what sounded like hail outside.  Like a good Earth Science teacher, she checked it out and investigated it with her students.  She reported in to the Live Doppler 15 Fury Weather Center that it was graupel – and she is right!

Graupel occurs when supercooled water droplets freeze on top of snowflakes.  Some refer to graupel as “soft hail”.  If you’d pick it up, it would quickly disintegrate or fall apart.

Credit: Jennifer Douglas

True hailstones, however, are formed in thunderstorms as a result of strong updrafts of air into the cumulonimbus storm clouds.  The strong updrafts suspend the ice particles aloft and allow them to collide with each other and get bigger and bigger.  Only when the hail stones are heavy enough to outweigh the strength of the air coming into the storm will they fall to the ground.


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