#nature #weather

Cloudspotting☁️

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Rabanindranath Tagore (Stray Birds)

“Clouds come floating into my life, no longer to carry rain or usher storm, but to add color to my sunset sky.”

I’ll be honest, I’m a CloudSpotter. I’ve been cloudspotting for over 5 years now, and actually come to think of it probably for about 20 years depending on how one defines “to cloudspot”.

Anyway, there’s more to cloudspotting than you think. There are 10 main cloud types that us spotters see frequently. Then there are a further 20 which are usually a bit rarer. THEN, you get hybrids between multiple types of cloud. So in effect there are oodles of clouds to spot.

Top 10

Have you ever wondered where the idiom "to be on cloud 9" came from? Well, you've got the folks at the Cloud Atlas to thank for that. Cumulonimbus was number 9 on their list of 10 main clouds. The cumulonimbus cloud is the largest riser cloud something reaching from its home as a low cloud all the way up to the high clouds! To be on cloud 9 would to be on top of the world!

BUT...when the new Cloud Atlas came out, our sparking friend the cumulonimbus was moved to number 10, which ruined the saying. The World Meteorological Organization relented and renumbered the clouds 0-9 so that we can still use our idiom...thanks WMO.

The top 10 clouds are the regulars:

  1. (Cu) Cumulus - the bright fluffy ones
  2. (Sc) Stratocumulus - a layer of cumulus
  3. (St) Stratus - we call it “low cloud” or “fog”
  4. (Ns) Nimbostratus - Harry Potters the ones where is rains all day long
  5. (As) Altostratus - featureless and high (boring)
  6. (Ac)Altocumulus - patches of cloudlets, high up.
  7. (Ci) Cirrus - really high wispy clouds
  8. (Cs) Cirrostratus - layer of high wispy clouds made of ice.
  9. (Cc) Cirrocumulus - high clumps of patchy clouds
  10. (Cb) Cumulonimbus - the big angry storm clouds.

See, Cb is at number 9. This fact alone makes me smile.

Clouds, by their very nature are not very well defined. Among the above 10 types, there are some 51 varieties of cloud which have names like stratocumulus cumulogenitus, altocumulus floccus and cirrus vertebratus.

So, why the different types?

Ultimately, all clouds form in the same way. When warm moist air cools the moisture leaves the air and forms tiny water droplets, or ice crystals, which form the cloud. If these droplets remain tiny and don't coalesce, you just get a cloud. If lots of droplets from they start to clump together (I used the posh word for this, coalesce) and eventually they fall from the sky and ruin your day.

Aside from this process, there are environmental factors which decide which kind of cloud you get. I'll not go deep into this because you don't really want to read it all so I'll just skim over the basics.

Altitude

The height at which a cloud forms is crucial to what kind of cloud it is. Higher up in the atmosphere, the temperature is cooler. This means you often get ice crystals forming instead of droplets.

This is where you'll find each of the 10 clouds types:

Altitude Class Altitude Clouds
Low Below 2,000 m Sc, St, Cu, Cb
Medium 2,000 - 6,000 m Ac, As, Ns
Hight Above 6,000 m Ci, Cc, Cs

Air Currents

As the air blows about at different speeds at differs altitudes, the clouds can be disrupted when they form. Kelvin-Helmholtz are a great example of this. If you have a cloud forming on a barrier between slow and fast moving air, the tops of the cloud are lapped up which makes them take on a wave appearance.

Cumulonimbus form with rapidly rising warm moist air which pulls the cloud to its infamously lofts heights. Similarly, air pressure zones can cause clouds to swirl like those in hurricanes.

Temperature

Clouds form differently in different temperature conditions. A period of warm followed by a sharp drop in temp can cause lots of clouds to form. Or if the air is stable but warm air rises steadily to create a temperature inversion, you may even get cloud inversions where the clouds form on the ground (looks sick from on top of a mountain).

Summary

So, this was a whistle stop note sharing some info about clouds. I hope you were looking for how ACTUAL clouds work, and not how the internet CLOUD works, or else you might have been disappointed.

I'd just like to point out that I'm position 29 in the WORLD for cloudspotting on the cloudspotting leaderboard. This might not seem impressive but let me tell you right now...it is. I will climb the leaderboard some more but in order to do so I need to visit the Southern Hemisphere, spot a cloud on Antarctica and experience a tornado. I'm working on it.


Created by Niall Bell (niall@niallbell.com)