Clouds Options

[Simon Kirby]

Been some interesting clouds around today. I was wondering why some clouds are white and some are almost black? So the sky was faily filled with white fluffy clouds with quite a bit of blue sky to be seen, but there were black clouds floating past underneath, and they were black like smoke from a burning tyre. How does that work then?

[shedboy]

Due to the amount of water vapour not allowing light through, hence they appear black or grey

[Simon Kirby]

Due to the amount of water vapour not allowing light through, hence they appear black or grey

Water vapour is transparent in the visible isn't it?

[JeffG]

Water droplets are also reflective and scatter light, hence less light gets through.

[Simon Kirby]

Water droplets are also reflective and scatter light, hence less light gets through.

So what is the difference between white clouds and black clouds - don't white clouds also contain water droplets?

[NWNREADER]

So what is the difference between white clouds and black clouds - don't white clouds also contain water droplets?

Look at it this way, the more dense something is the more visible it seems to become.
Fog is one example, and many politicians give the same effect.

[Biker1]

So what is the difference between white clouds and black clouds - don't white clouds also contain water droplets?

All clouds consist of water droplets.
Water vapour is all around us in the atmosphere and is invisible.
The amount of water vapour in the atmosphere is measured in relative humidity %.

Clouds usually look grey when we are directly underneath them. This is because sunlight does not shine directly on the bottom of clouds, but rather shines through from the tops of clouds.

Sunlight gets blocked more when the cloud is thicker. So the bottom of the cloud looks dark. If the cloud is thin, it may appear more white because there is less cloud matter to block sunlight.

If you are under a tall dark cloud, wait until it passes, and look at it's side. The side of the cloud will be illuminated by sunlight, and thus all white. So, the brightness of the cloud (white versus grey or black) has a lot to do with where you are standing and the thickness of the cloud.

Sunlight has to travel thousands of feet through the cloud to our eyes. As the light travels through the thick cloud it gets scattered, absorbed, and reflected away from our eyes. In the end, this means that less and less light reaches our eyes.
However, if the cloud is thin, then we will see much more of the light, and the cloud will appear much more white.

And finally, if you aren't underneath the cloud then the tall and thick cloud is illuminated by sunlight. This light does not travel through the cloud, but rather reflects off the side of the cloud and into your eyes. (Remember, all colours of light are reflected equally, that's why it's white). However, if you walked underneath this cloud, it would look much darker.

[Turin Machine]

Ouch! Chilly man, real chilly.

[Simon Kirby]

All clouds consist of water droplets.
Water vapour is all around us in the atmosphere and is invisible.
The amount of water vapour in the atmosphere is measured in relative humidity %.

Clouds usually look grey when we are directly underneath them. This is because sunlight does not shine directly on the bottom of clouds, but rather shines through from the tops of clouds.

Sunlight gets blocked more when the cloud is thicker. So the bottom of the cloud looks dark. If the cloud is thin, it may appear more white because there is less cloud matter to block sunlight.

If you are under a tall dark cloud, wait until it passes, and look at it's side. The side of the cloud will be illuminated by sunlight, and thus all white. So, the brightness of the cloud (white versus grey or black) has a lot to do with where you are standing and the thickness of the cloud.

Sunlight has to travel thousands of feet through the cloud to our eyes. As the light travels through the thick cloud it gets scattered, absorbed, and reflected away from our eyes. In the end, this means that less and less light reaches our eyes.
However, if the cloud is thin, then we will see much more of the light, and the cloud will appear much more white.

And finally, if you aren't underneath the cloud then the tall and thick cloud is illuminated by sunlight. This light does not travel through the cloud, but rather reflects off the side of the cloud and into your eyes. (Remember, all colours of light are reflected equally, that's why it's white). However, if you walked underneath this cloud, it would look much darker.

Yes, I found that on the internet too, and I'm not convinced. The clouds I saw yesterday were very thin, very low, and very dark, and they were scudding past underneath white clouds on a relatively bright day. It looked to me as though the cloud itself was dark, like smoke, and it's darkness wasn't simply that it didn't have the sun shining on it.

[NWNREADER]

Yes, I found that on the internet too, and I'm not convinced. The clouds I saw yesterday were very thin, very low, and very dark, and they were scudding past underneath white clouds on a relatively bright day. It looked to me as though the cloud itself was dark, like smoke, and it's darkness wasn't simply that it didn't have the sun shining on it.

A Radicalised cloud, perhaps......

[Biker1]

Yes, I found that on the internet too,

What do you mean "found on the internet"?
All of the top of my head old chap!!

[Andy Capp]

Simon, perhaps what you saw weren't meteorological clouds.

[Biker1]

Simon, perhaps what you saw weren't meteorological clouds.

[Simon Kirby]

Simon, perhaps what you saw weren't meteorological clouds.

It was unusual weather but I'd say what I saw were clouds, albeit unusual low-level cloud.

[JeffG]

Clouds are full of data and people's files these days. Maybe that was it.

[Exhausted]

I understand that every one of them has a silver lining.

[greenmeanie61]

This may help! There an app too.

http://cloudappreciationsociety.org/