I've always had a fascination for the weather. Especially violent weather; if I hadn't become a mild-mannered high school biology teacher, I'd have been a tornado chaser. One of my favorite movies is Twister, and yes, I'm well aware of how ridiculous it is, but still. Who didn't cheer when the Bad Meteorologist got smashed to smithereens, and the Good Meteorologist and his wife survived and decided they were still in love?
Okay, maybe it was just me. But still. There's something compelling about weather, which is why I frequently give my wife urgently-needed updates about frontal systems in South Dakota. Like everyone does, right?
Anyhow, having been a weather-watcher for years, I was absolutely flabbergasted to find out that recently, the powers-that-be in the meteorological world have added twelve new types of clouds to the International Cloud Atlas. Which is a book I didn't even know existed. I mean, I've known since I was a kid and got a copy of The Golden Guide to Weather that there were different sorts of clouds, classed by height, shape, density, and pattern (if any) -- with wonderful names like altostratus and cirrus and mammatocumulus. It honestly never occurred to me, though, that there was an entire atlas devoted to them, much less that there might be new ones. After all, people have been watching the skies for millennia, not to mention describing it and drawing pictures of it. How could they see anything truly new?
Well, it turns out that some of the new ones only form under really specific conditions. Take, for example, one of the newly-classified cloud types, named cavum, sometimes known as a "hole-punch cloud" or a "fallstreak hole." This occurs in an altocumulus cloud bank, when something causes sudden evaporation in a region, leaving behind a hole through which you can see the blue sky. It's sometimes triggered by an airplane or even a meteor.
Another new one is the murus cloud, or "wall cloud." Although this one has been seen many times, especially if you live in the midwestern United States, it just recently received its own nomenclature. It's a part of a cumulonimbus formation -- the kind of cloud that gives rise to thunderstorms and tornadoes -- and results from an abrupt lowering of the cloud base. This indicates the area of strongest updraft, which is why murus clouds are a good indication that it's time to head to the storm cellar.
One last one is the asperitas formation, which has an undulating, underwater appearance. While they look threatening, they're more often seen after a thunderstorm has passed, and usually dissipate quickly without any further violent weather.
Anyhow, I was really surprised to hear that those only recently got their own official classification. I guess it just goes to show that there is still a lot to be learned from the things we look at every day. Speaking of which, it's time for me to check the NOAA forecast site and see about those frontal systems in South Dakota. Carol is waiting for her update. You know how it goes.