Amazing Kelvin-Helmholtz waves over Birmingham

[D18]

Awesome shot! I had no idea that phenomenon was possible.

Now, as near as I can figure, those clouds must be virtually overhead of this guy here!. I don’t know why I thought of that.

[lieu]

Bad freakin’ ass! That looks almost apocalyptic. Appreciate you sharing it here.

[Clothilde]

Ogre, this is an awesome photo! Have you tried submitting it to the local tv stations? I know that the weather guys at WSFA here in Montgomery would have a fit over something like this. They’d probably put it on the air, too.

[Eleanor_of_Aquitaine]

There’s a video on Dan Satterfield’s blog (local weather celebrity):
http://blogs.agu.org/wildwildscience/2011/12/17/magic-clouds-in-the-magic-city/

[Clothilde]

Well, I posted too late. I saw the local 5:00 pm news today and the weather guy aired a photo taken from somebody else who saw it at Birmingham airport. He did at least pronounce Kelvin-Helmholtz correctly and explained what it was and how it formed, so I was impressed.

So now I say send it to Brian Williams…

[medstar]

It looked like several breaking waves on the ocean, imagine if those were real water waves; perfect for surfing.

[Autolycus]

Pretty awesome stuff!

[Robot_Arm]

More coverage:

Giant Tsunami-Shape Clouds Roll Across Alabama Sky

[rbroome]

@Ogre

Check this out

I pulled over on the interstate to take this photo. What you’re looking at is a phenomenon called a Kelvin-Helmholtz instability. The ridgeline directly ahead had been cloaked in heavy fog all morning, and as a cold front came through, it sent strong, laminar winds above and along the ridge. This resulted in lower pressure just above the fog layer. The fog was lifted off the mountain and “rolled forward” in the distinctive way you see by encountering the laminar flow aloft.

This was really, really cool to see. At its peak, there were 7 well-formed waves lined up down the ridge. This is a phenomenon you see fairly commonly in cloud layers, but I’ve never, ever seen it on the ground.

thats cool!
you need to put that up on weather underground!

[Ogre]

@WordMan

+1.

Only on the 'dope…meteorological wackiness and you play some mean guitar, too.

Maybe we’ll work “Wipeout” into our next set somehow.

Clothilde: No, I haven’t submitted it to any local weather folks. It’s actually gained some steam in the local press (and abroad) since it’s such a very, very rare occurrence. Most of the local guys have pages up and people have now sent in hundreds of shots of the event.

Eleanor: Now, that’s a cool page, and a great illustrative video of how the phenomenon works. Thank you!

Robot Arm: Wow. It really has picked up steam (although I can’t help but notice the amount of religious and semi-religious hysteria it has stirred up in some people. Weird.)

[Duke]

The Daily Wh.at has a few more pictures, and a video.

[Ogre]

Yeah, all the photos and vids I’ve seen so far were lifted from the original weather blog I mentioned earlier.

Also, I’m not going to pitch an internet-wide fit about this or anything (and I’ve spoken to him about it), but the meteorologist posting under the name zensunnioracle has a slight inaccuracy in his description of the process.

As Redditor/meteorologist zennisunoracle explained, Kelvin-Helmholtz waves form in the morning, when the atmospheric layers closer to the Earth’s surface are more stable than the layers above them. Wind shear destabilizes the top of that stable layer, causing the stable air to lift, cool and condense into a visible pattern that looks like the top of a wave.

Normally, he would be exactly right, but the conditions last Friday were just a bit abnormal. In this case, the moisture was already condensed in the form of a dense fog on the mountain, so there was no condensation upon uplift. I really wish I had thought to stop and film the process from the beginning, because I watched it happen, and it was fascinating. You could actually see the fog start to destabilize, start tossing a bit like water, then begin to form into peaks, and finally to lift up to the level of the wind shear and roll over.

[Alka_Seltzer]

Great photo. I’m reminded of the drowning of Numenor…

[Yllaria]

@Ogre

Yeah well, this is how much of a nature/weather/science geek I am: I’m pretty sure I was the first person in the city to identify it as a K-H instability. We were driving on the interstate, and I saw the fog (really a very low cloud layer) start to destabilize in places. As we were passing into the downtown area, I saw the beginnings of telltale “peaks” in the fog spaced at regular intervals. Right then, before any distinctive wave forms were discernible, I shouted “Kelvin-Helmholtz!” I can’t really imagine that anybody else on the planet beat me to the punch on that one.

I broke off in the middle of a conversation with my wife about Christopher Hitchens, and she momentarily thought I’d lost my mind. Within just a couple of minutes, the waves were fully formed, and we stopped on the side of the road to take photos.

Nice description. Thanks for sharing this. Amazing is the right adjective.