October 23, 2008 Hailstones

I always thought hailstones were round. Perfect little spheres, actually. I have only a vague sense of how hail is formed, but I recall it involves rain falling down, getting caught by a thermal, tossed back high into the atmosphere where it freezes, then it falls some more and picks up some more water molecules, then it gets tossed back up again, ad infinitum. Well, actually, ad it-gets-too-heavy-for-the-thermal-to-mess-with-it-and-so-it-falls-down-to-the-ground-um. I think.

But I always imagined the little droplet, y’know, spinning as it got tossed around. Hence the perfect sphere.

But I was out in a hailstorm today, visiting the Berberville schools, so I had time to take a closer look. It hails pretty regularly these days…a month ago, it was raining nearly every afternoon; now, it’s raining or hailing nearly every day. No snow since that first storm, lhumdullah, and the temperatures have mostly been in the 50s. (Well, not right now. Right now, it’s 38 outside, and 47 inside. So if I had windowsills, they’d be refrigerator temperature; as it is, I don’t bother refrigerating my food. I don’t think the extra 10 degrees makes much difference, and it’s been in the 40s all day. Inside. {shiver})

So as I walked the kilometer or so back from the school, I caught several hailstones on my glove and took a good look at them. They weren’t round. They were almost perfect cones, actually. Their bottoms were rounded, not flat, but they were otherwise cone-shaped. Like an ice-cream cone whose scoops are almost licked away, except more shallow. Exactly like the Apollo re-entry vehicles, come to think of it. And maybe for the same reason? This little ice pellet was bombing its way through the atmosphere and its bottom was melted and sheared by the air pressure of terminal velocity?

Or maybe hailstones are just funny at high elevations. I live somewhere between 6500 and 8500 feet, depending which map you look at, and since I’ve spent nearly all of my life within a few hundred feet of sea level, I’m constantly surprised by the differences of life at elevation.

(If you have any insights, please feel free to post a comment or shoot me an email. I'm actually curious about this.)