This winter we've had six rounds of wintry mix in the area from freezing rain to sleet and even some graupel. Today I'll show you the difference between sleet and hail and take you through process of what causes graupel.
Hail is more typical in storms during the warm months between April and September. Hail is the result of strong updrafts or rising currents. The updrafts push raindrops high into the sky where it is cold enough to make ice.
The updrafts will keep the hail in the cloud for about 5 to 10 minutes. So it will melt and then freeze again over and over as it goes up and down inside the cloud. When the chunk of ice gets too heavy the updrafts won't be able to keep it suspended so it will fall.
Sleet occurs during the winter months and is caused by rain falling into a freezing layer closer to the ground. As the raindrops fall into the pocket of very cold air, they freeze and become small ice pellets. You have to have freezing temps at least 5,000 feet for the raindrops to turn into sleet or it will be just freezing rain.
So hail and sleet form differently and hailstones are normally much larger than sleet pellets and cause more damage.
We even experienced graupel this year. This is a styroform ball type of snow. This is when supercooled droplets freeze on falling snowflakes and get covered in ice. This happens when the snow falls into a slightly warmer and moist layer in the middle of the atmosphere.
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