© 2024 Louisville Public Media

Public Files:
89.3 WFPL · 90.5 WUOL-FM · 91.9 WFPK

For assistance accessing our public files, please contact info@lpm.org or call 502-814-6500
89.3 WFPL News | 90.5 WUOL Classical 91.9 WFPK Music | KyCIR Investigations
Play Live Radio
Next Up:
0:00
0:00
0:00 0:00
Available On Air Stations
Stream: News Music Classical

Spring weather changes can bring damaging hail. What makes it happen?

Hailstones
Cody A
/
Unsplash
Hailstones

Every week WAVE 3 meteorologist Tawana Andrew breaks down what we know and what we don't about the climate and weather here in Louisville.


Bill Burton: It's time for us to take a look at the Science Behind the Forecast as I am joined by WAVE 3 meteorologist Tawana Andrew. Good morning, Tawana.

Tawana Andrew: Good morning. Today's topic is one aspect of severe weather that I really don't like, at all.

BB: No, it can be a little terrifying. We're talking about hail today and the different sizes of it. How fast it can come at you. All have the terrifying things we have in store for you with the latest Science Behind the Forecast. Enlighten us, please.

TA: Okay, so hailstones form when updrafts throw raindrops into sub freezing portions of the atmosphere, so you're going higher up in thunderstorms, it gets colder, and then these raindrops start to freeze. Now the hailstones will grow larger and larger as they collide with additional water droplets that will freeze onto their surface. So you have an option of the water droplet freezing either slowly or instantaneously. If water droplets freeze instantaneously, then you end up with this cloudy ice that forms as the newly formed ice basically is trapping air bubbles. If the water droplets freeze a little bit more slowly then the air bubbles can escape. And then the new ice will be clear. And this is the reason why you have the rings inside of the hailstone if you ever cut one in half.

BB: Very cool.

TA: Literally, very cool.

BB: Well played.

TA: Thank you. Thank you. So the rings of these clear and cloudy ice in the hailstones are due to the varying temperatures and water content that they encounter as they travel throughout a thunderstorm. So a lot of people think of the wind inside of a thunderstorm moving up and down because we talk a lot about updrafts inside of a thunderstorm. But it also moves horizontally, that wind within a thunderstorm, too. So as the wind is throwing this hailstone around, it's changing the environmental conditions and the changing what the layers of the hailstone really become. Now, here's the part where I might scare some people and it's fascinating, but it is a little scary. So, so for small hailstones. So let's say pea to nickel sized hail, the expected fall speed is between 9 to 25 miles per hour.

BB: Okay. All right, fast, but not too terrifying.

TA: Exactly. Within a severe thunderstorm, you can get quarter to golf ball sized hail. And the fall speed for that on average is between 25 and 40 miles per hour.

BB: Okay, you have my attention.

TA: Now in the strongest supercells like the ones we hear about in parts of Texas, Oklahoma, Nebraska, you can get hail tennis ball to grapefruit sized in those storms, the fall speed for those, 44 to 72 miles per hour.

BB: I don't want something the size of a grapefruit coming at me at 72 miles an hour.

TA: People drive that fast on the freeway. So that yeah, that is pretty quickly and then the most dangerous hailstones. So the ones where the diameter can exceed four inches, can fall at over 100 miles per hour.

BB: Okay, Alrighty, then.

TA: So maybe now when we have severe thunderstorm warnings, everybody will head a little bit further inside.

BB: That sounds like a wise choice. Well, there's a lot of information there to digest, but we certainly understand it a lot better just to how dangerous hail can be. Thanks to the latest edition of Science Behind the Forecast with WAVE 3 meteorologist Tawana Andrew. Thanks for the knowledge, Tawana.

TA: Of course.

This transcript was lightly edited for clarity

Bill Burton is the Morning Edition host for LPM. Email Bill at bburton@lpm.org.