December 22, 1998 transcript # 265-2
Subject(s): differences in precipitation
Title: Listener Question: Hail, Sleet And Freezing RainHi, I'm Dave Thurlow from the Mount Washington Observatory and this is The Weather Notebook. Today we have a question that comes from Megan Burt-Kidder, a New Hampshire Public Radio listener:
Megan: "I've always been curious as to what the subtle differences are in the atmospheric conditions that allow either sleet, hail or freezing rain."
Well let's look at each one individually. First up is hail, which falls mainly during the summer. Hail falls from thunderstorm clouds which extend miles high into extremely cold air. Updrafts bring raindrops from the bottom the top of the cloud where they freeze into ice pellets. They then fall only to be blown back up where any coating of rain freezes and the hail stone grows layer by layer for each time the up-down cycle occurs. The hailstones, sometimes the size of baseballs, finaly overcome the updrafts and fall to the ground.
Now sleet falls in the winter if and when when the air temperature is below freezing near the ground and above freezing up in the clouds. Rain forms up where it's warm and falls into the cold air, freezing into little pieces, what we call sleet, on the way down.
Finally freezing rain is almost like sleet except it freezes after it hits the ground forming a glaze of ice. So hail falls from summer thunderstorms and each stone can be as big as a pea, a quarter, or a grapefruit, sleet and freezing rain fall in the winter, sleet being ice pellets and freezing rain being rain that freezes whe it hits the ground.
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