These can be found at: New Scientist dot com



Fallstreak holes

These are crisp gaps in mid or high-level cloud layers, below which dangle trails of ice-crystals.

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Roll cloud

This is a horizontal tube of cloud that forms in the cold downdraughts that spread out ahead of an approaching storm (or, less commonly, at the tail end of a decaying storm).

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Pink UFOs

A stack of altocumulus lenticularis clouds hovers over the Alpujarra Mountains in southern Spain, stained red by the rays of the setting sun.

Lenticular clouds (Latin for "lens-shaped") are a common sight in mountainous regions.

They have often been mistaken for UFOs.

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Altocumulus lenticularis - how they form

Lenticular clouds are created when a stable layer of humid air is forced to rise over high ground, condensing its moisture into cloud.

Cap cloud

When a cap cloud materializes, it tends to look like a hat, perched upon the mountain's head.

It forms when a stable air stream rises to pass over a peak, cooling as it does so.
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Virga

These clouds look a bit like jellyfish floating in the sky.

The "tentacles", which you can see hanging down, are called "virga".

They are essentially rain, or snow, that evaporates away before ever reaching the ground.

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Mammatus at the base of a storm cloud

Mammatus clouds (from the Latin for "udders") are associated with unstable, often stormy weather - though they can also be seen in relatively calm condition, long after bad weather has passed.

Their appearance is the result of pockets of cold, saturated air sinking rapidly from the top of a storm cloud, forming downward bulges or ripples at the base.

Their shapes can vary considerably, from long, undulated ripples covering many square kilometres, to smaller patches of near-spherical pouches.

This rather menacing display of globular mammatus, contorting itself over a college sports stadium in Hastings, Nebraska in June 2004, is the latter type.

Kelvin-Helmholtz

Looking like enormous waves breaking on the shore, this type of cloud is rare and fleeting - lasting no more than a minute or two.

The distinctive breaking-wave shape is caused by wind shear.

Beautiful, thanks for posting those.

Those are REALLY pretty. My mom always loved looking at the clouds. She could always make something out of them and I guess I picked that up because I like looking at them myself.

Absolutely fascinating! Thanks Nancy!

Those are neat..

I like this one..

Beautiful Nancy, you always find interesting stuff.

Very cool!

Beautiful photos!!
Thank you for posting the link too, Nancy!

those are amazing! Thank you.

Very cool Nancy..... Loved them.

Thanks you Nancy for posting these. From someone who loves to lay in her hammock and look at the sky, I love these!

So beautiful Nancy!...Thank you.It brings back memories of laying in the grass as a child and making pictures out of the clouds.Of course they couldn't compare to these beautiful clouds!