Tornado Corridor Impressions

That's an aerial shot of the recent tornado's path near my house; you can see the major damage corridor as a lighter-colored diagonal line where all the trees are down. (The photo is a scan of a newspaper photograph from the Concord Monitor; perhaps NH's best newspaper.)

[Geekly aside: To orient yourself in the above photo; the plane that took that aerial photo was at low altitude over the dead-center of this Google map http://tinyurl.com/6ne8ov. The plane was headed North; the damage track in the photo heads NNE. In the photo, you can just see the blue of the westernmost part of Northwood Lake in the picture's upper right.]

On Sunday, a friend invited me on a short motorcycle ride with some of his buddies through the area recently hit by the tornado.

I'd purposefully stayed away from the tornado damage corridor in the days immediately following the storms: The National Guard was called out briefly, and FEMA plus numerous State and private agencies were all brought to bear. The 20+ mile track also was swarming with utility trucks to restring wires and restore services.

Incredibly, the area was clogged with sightseers, too; US Route 4 runs through here, and traffic was bottlenecked by cars parked illegally while people jumped out to take pictures. I thought the best thing to do was to stay away to avoid being an obstacle.

But by the weekend, the spectators were mostly gone and we could pass through the area without getting in anyone's way.

It was impressive to see. The forces involved were amazingly constrained: total destruction here, and then, in the space of a few tens of feet, hardly any damage at all.

One of the things that impressed me most was the way the tornado chewed through living forest. This isn't at all like the damage you see in classic photos of midwest tornadoes roaring across a dusty field. This was something else.

To explain, I have to ask you a question: Have you ever felled a big tree? I mean a BIG tree, like 100' (30m)?

If you're close to it, a big tree makes an incredible noise as it falls. As the tree's huge weight starts to shift, the trunk protests with long groans and gunshot-sharp pops.

If you're the one felling the big tree, you retreat in a safe direction, away from the fall line. Right behind you, groans and pops from the tree trunk accelerate in tempo as the wood's fibers stress and fail. Way, way above you, you can sense the falling tree quickly gathering momentum.

Even if you expect it, and even if your conscious self knows you're safe, the sound of a big tree starting to fall wakes up some primal circuitry buried in the subbasement of your brain: You feel a burst of adrenalin as the ancient "Flee!" wiring lights up. "Run!" it says. "Something heavy is falling!"

As the tree falls faster, you begin to hear a perceptible whoooooshing sound as the branches sweep the air. The falling tree's branches rake the neighboring trees; a wood-on-wood clatter that builds into a sustained white-noise roar of breaking branches.

Then the tree hits the ground and you can feel the concussion both through your feet and also in your chest, the way you can sometimes feel loud fireworks reverberate there.

Incredibly, a big tree will often bounce after hitting the ground. You then hear a second, less intense impact followed by a loud, slowly diminishing clatter and crack as the tree settles into its lowest-energy resting position on the ground.

Simultaneously, you hear a gentler whooshing overhead as the branches of the surrounding trees recover from having been swept by the falling giant; as you watch, the surrounding branches whip back into position and the forest canopy rearranges itself around the new hole you've created.

Let me assure you: Watching a big tree come down nearby is impressive.

Now take a look at this picture again. This is just maybe 1/10th of the total damage path from the tornado. Look at the trees. Many of them were mature giants, and each one--- each one--- made noises like the above as it fell.



And remember that the photo only shows 1/10 the total damage. So, take the noise of the sound I described above and multiply it in your mind by the number of trees you see in that photo, times 10. That's the aggregate sound of this tornado's tree damage.

But there's more. And we'll talk about that tomorrow.