Monday, April 3, 2017

There Are "New" Clouds In The Sky - 11 Of 'Em

A really cool type of cloud called aspirates. The International
Cloud Atlas has deemed these a "new" type of cloud
classification, though these clouds have existed forever.
Bonus: These clouds are really cool, but not dangerous.
As a weather geek, I'm always obnoxiously looking up at the sky checking out the shapes, formations and ever-changing cloud movements up there.

Apparently, there's a lot of people like me, because there's something called the International Cloud Atlas, that lists and describes all the different kinds of clouds that can happen.

Recently, the International Cloud Atlas has deemed that there are eleven "new" clouds that we can look at.

To be honest, the new clouds the Atlas lists have always existed, but hey, you have got to account for everything that's in the sky, right.

The reason these clouds are "new" is they didn't really fit any previous catagory of cloud, so they had to get their own groupings.

Five of the clouds are highly localized clouds that form from very, limited and specific circumstances.

For instance, there are flammagenitus clouds, which form near wildfires, and cataractagenitus clouds, which form from the spray generated by waterfalls.

My favorite "new" cloud, one that is actually somewhat rare but something most of us have seen at least once in our lives without realizing it, is asperitas clouds.

According to National Geographic recognition of Asperitas clouds came from citizen scientists.

Kelvin-Helmholtz clouds over Breckenridge, Colorado
in October, 2015. Photo by Stacy Nicholson and Skip Wood.
That's another plug for citizen scientists that I want to highlight.

These are normal, every day people that don't have a lot of training in science, but they observe what's going on in the natural world around them, and report that information to trained scientists.

Scientists, and their tools and instruments, can't be everywhere at once, so local people observing local phenomenon, can be the eyes and ears of meteorologists and any other scientists.

People - citizen scientists - hooked up with a group called the Cloud Appreciation Society to note the type of cloud they were observing, the Asperitas clouds, didn't really fit any existing category in the Cloud Atlas.

So, finally, Asperitas clouds are in the Atlas. Congratulations!

Other clouds added to the the Atlas are Kelvin-Helmholtz clouds, which I also mentioned not long ago. They look like a series of breaking waves in the sky.

Another fascinating cloud added to the list are fallstreak clouds. You see it when there's a layer of mid-level clouds overhead, and there's a circular area in those clouds where the sky is clear, and you can see streaks of what looks like rain coming out of where the hole in the clouds just formed.

What typically happens with fall streak holes is that the clouds are made of supercooled water - its still liquid, but the temperature is below 32 degrees. A plane flies through the cloud, causing the supercooled water to freeze in patch, and form ice crystals that begin falling toward the ground.

That's the streaks you see beneath the hole in the clouds. This process can move the air around the center of the hole, and the hole can expand as more droplets freeze and fall, or dry air intrudes and they evaporate.

To conclude, here's a timelapse of really cool asperitas clouds:

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