Like Larry the Flying Guy on Facebook!

Monday, February 17, 2014

Why there is no reason to fly through a thunderstorm in peacetime

Like Larry the Flying Guy on Facebook:

Follow on Twitter, too:

There is an oft-repeated maxim in aviation weather: There is no reason to fly through a thunderstorm in peacetime. While this is attributed to a sign in a particular Air Force base (although which base changes depending on who's telling the story), it's probably hanging somewhere around almost every military aviation operations office—and if it isn't, it should be. Check out the picture below to see why:

Picture taken over Africa from the International Space Station. Courtesy of the Image Science & Analysis Laboratory, NASA Johnson Space Center. Click image to embiggen.
What's most remarkable about this picture is that this isn't a particularly remarkable thunderstorm. It's a garden-variety cumulonimbus, as evidenced by its lack of a prominent overshooting top. A large overshoot would indicate that the convection inside is stong enough to bust through the "cap" of the troposphere. This one has a nice, clearly defined core, but gets squashed flat pretty quickly once it reaches the tropopause. (The NASA-provided caption for the original picture has a short, easy-to-read description of what causes cumulonimbus to form, grow, and get squshed. It's impressively non-technical, as far as NASA writings go.)

So what? Why do you care about a picture of run-of-the-mill thunderstorm? Because despite this particular storm's "meh" status among thunderstorms in general (this one is the kind you'd go out on the back porch, kick back with a glass of your favorite beverage, and watch roll through), it still contains an immense amount of energy inside it.

How much energy? To give you even a notion of the power inside an average thunderstorm, look at the towering cumulus at the right of the picture (the smaller puff of cloud just ahead of the thunderstorm itself—see this picture if you need help). Notice how much smaller that tower is than the thunderstorm is? That TCu (towering cumulus) isn't even a thunderstorm yet; it's a thunderstorm still in the process of being formed.

Nonetheless, that "little" tower is still bigger than the mushroom cloud over Hiroshima was. That's right: for all we humans think we've "mastered" nature, and for all the fury we think we can unleash, the first atomic bomb wasn't even as big as Mother Nature putzing around. Don't take my word for it; see it for yourself in this picture taken from the Enola Gay:

Image 542192 from the U.S. National Archives. The top of the mushroom cloud is 1/2 to 1/3 as tall as the towering cumulus above.
While little boys like Little Boy release their energy on a scale of milliseconds to seconds, thunderstorms operate on much longer time scales (like minutes to hours). This makes them seem less fearsome than an atomic bomb, but inside each one of them is much, much more power.

How much more? A meterologist at the University of Chicago calculated way back in 1953 that it is 50 times more.

Is that enough of a reason for you not to fly through a thunderstorm in peacetime?

No comments:

Post a Comment