Thursday, 6 June 2013

Clouds (Sky Sheep)

So, it took some convincing to get both girls to the point where they accept that clouds are indeed made of water and not of fluff (and most disappointingly not of cotton candy, which I was able to debunk by pointing out it's lack of pinkness). I can't take all the credit - the Cyberchase weather watcher episode on fog may have helped a bit, because that's just a cloud on the ground. This doesn't explain the variability of clouds though - different shapes, degree of fluffiness (which isn't, but should be, a cloud measurement scale) and what Bunny asked about - colour.

Now, while I am not in any way a weather expert, I am a sailor. Which means weather has always been an interest, because when you are in the middle of a lake with a large metal pole you might want to know when lightning is coming (especially while in charge of other people's children who also have metal poles). I know which shapes of clouds mean a lovely day of sailing and which ones means get your butt back to shore. But what's with all the different shapes and colours if they are all just made of water? Bunny is not the first to wonder this - the first International Cloud Atlas was first published in 1896 (not to be confused with that recent movie that really has nothing to do with clouds at all).

The colour thing is pretty simple actually - density. Because clouds are made of water or ice crystals they break up light on it's way through which combine to make white (all light colours together make white - which by the way doesn't work in paint or playdough, that makes weird grey-mud-brown). When the clouds get thick or piled up then the light doesn't go all the way through and it looks darker - so nothing really changed composition wise, there's just more of it. If you get a whole bunch of clouds together they can also shadow each other creating an even darker or variable look.

Cool Aside Thing: When the light doesn't make it all the way through the water droplets in the atmosphere and bounces around in them, it breaks up into individual colours and we get rainbows. The water acts like a prism (think Dark Side of the Moon album cover but with a water drop) and reflects the light back at us all pretty and happy.

Now, shapes. This has also to do with density and also where they are in the atmosphere. I have borrowed this handy kid-friendly cartoon chart for some shape basics:

See that tall puffy guy there on the right? He's the one that tells you to get your boat to harbour and make some popcorn for a light show. The other guys are pretty friendly. Now, before we get into any discussion about the above I'd like to put a disclaimer for any meteorologists reading this - I know there are sub-types and jargon and more classifications than this but we're not going to go there, ok? OK! There is an awesome cloud poster HERE from Environment Canada though if you want a bit more detail or just a cool ID poster for your wall to go next to your bird one.

A bunch of the names there are combos of each other which can't possibly be a coincidence, so here's why:
Cirro: curl, high
Strato: layer
Cumulo: heap
Alto: mid 
Nimbo: rain, precipitation    

So see - our cumulonimbus thunderbuddy there just means "heap of rain" cloud. Which is actually a pretty accurate descriptions of our last few weeks here, in which I sailed boats in my office parking lot. Today was very gray so it's a sky full of stratus, which decided to start raining right when soccer started, so I suppose if I look at my list below they were nimbostratus, but that's not fair because you haven't read that far ahead and now I'm cheating.

Quick overview of the main cloud types:

These are the flat gray clouds that often make up what we would just call a "gray day" - no sky visible at all. Like a sky fog - covers everything. Sometimes they drizzle.

Dark gray and rainy looking, and often are rainy and that's why they are nimbos - that continuous light or steady rain that lasts a while. This was soccer today - steady (and windy, but we're not doing wind).

Wispy clouds that get blown around like streamers. Way up high and these are happy nice weather clouds. If you've got these your picnic is A-OK.

Happy picnic clouds

Gray and poofy. They can mean thunderstorms are coming later, particularly in the summer.

Gray and cover the whole sky, but higher than the stratus ones. More rain forebearers.

Little puffballs, like someone flung a bunch of cotton swabs up there. Sometimes they look like fish scales in which case you can call it "mackerel sky". I have no idea why a mackerel, it does seem an odd fish to choose. I feel like for here we should use "trout sky" or "bass sky". Maybe "salmon sky".

Fishy sky

Really thin white clouds covering the entire sky.

These are your lying on your back looking at shapes clouds. Big, puffy and shaped like dragons, trains, and sheep (I really like sheep). The only bad thing about these guys is sometimes they get together and can turn into the next ones, which is awkward if you are doing your cloudwatching far from shelter.

Sky Sheep!

Thunderstorm! Big and tower or anvil shaped. The bottom is dark gray, and sometimes you can see the sheets of rain coming down (and towards you). The condensation of all that water produces energy and then we get lighting, thunder and tornadoes. If you see this one remember to put down your deck umbrella.


Now, don't get me wrong, I love a good thunderstorm in the right situation. That situation is not on a boat with a large metal pole or in a small tent that is falling over, because I've tried both of those and I don't recommend them. I prefer a cup of tea and being on the inside of a large window.

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