Cloud Types & Formations

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Base height : above 20,000 ft (6000 M)
Composition : Ice crystals, primarily
generally quite thin with a hair like or filament appearance. Another name for cirrus is mares tails.		covers large areas of sky in ill defined blankets. Generally thin enough to allow sunlight to shine through

Cirrus clouds are a common occurrence, but have proved to be very difficult to photograph, due to their delicate appearance.	Patch work Cirrocumulus	A patch of cirrostratus, diffusing early morning sun


	Banded cirrocumulus


Base Height: 6,500-20,000 ft (2,000-6,000 M)
Composition : Water droplets, primarily. If air temperatures are cold enough can also contain ice crystals. Midlevel clouds can produce light precipitation
Distinct cloud elements, can have a patch work or linearly banded appearance		Produces a uniform diffuse coverage of sky. Individual elements & clouds can be difficult to see

Patch work altocumulus at sunset

Banded altocumulus, again at sunset, also called a mackerel sky.		Banded altostratus, which possibly started life as a condensation trail.


Base Height: Below 6,500 ft (2000 M)
Composition:Water droplets, may contain icy crystals & snow in cold climates. Can produce light/moderate precipitation
Usually the lowest of clouds, often appears as an over cast deck with little or no structure evident.	Usually puffy (think popcorn or cotton wool) with distinct edges & signs of vertical development. Vertical development can be further enhanced by thermal convection to push cumulus clouds into the multi layer category (see below), to form Towering Cumulus or even Cumulonimbus clouds	Stratus clouds that have reached ground level form fog.

07/03/03. After a day of almost unbroken heavy rain, the sun peeks our beneath a sold plate of stratus.	Ranks of fair weather cumulus, 21/08/02	A low lying fog bank, taken 5/08/02 04:42

		A low lying fog bank starting to lift, with a distinct updraft swirl on the RHS of the picture. 21/08/02, 07:16


Base Height: Varies, can span all cloud layers & reach heights in excess of 39,000 ft (12,000 M)
Composition : Varies, generally water droplets, higher sections can contain ice crystals. Can produce heavy precipitation
	Cumulus clouds enhanced by thermal convection. Further enhancement can produce Cumulonimbus clouds (see right)	One of the largest individual cloud formations, they can extend to heights of 60,000 ft. The tops of CB clouds have an easily recognisable 'anvil' shape & can produce lightning, thunder, heavy rain, hail strong winds & tornados
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	Towering cumulus pictured 30/5/02. This developed rapidly into a Thunderstorm, drifting E towards Halifax	The main problem with observing CB clouds, is their size. If a thunder storm develops,it is generally on top of us before we know about it. The above shows part of an 'anvil' poking above mixed lower level clouds.

	Cumulus towers taken during an outbreak of thunderstorms, which hit northern England 3/6/02	Two CB clouds 02/02/03. 5 hours later 5cm of snow fell on Todmorden


Artificial high clouds produced by the rapid cooling of moisture from aircraft jet engine exhausts into ice crystals
	On the left : Three con trails in varied states of diffusion. On the right : single relatively fresh con trail surrounded by a mixture of cirrus, cirrocumulus & cirrostratus.

Lens shaped clouds formed by strong winds over high/rugged terrain.

Although the hills around us are not particularly high, lenticular clouds are produced quite regularly. They tend to occur either early morning or late evening, the ones above were at 07:51 21/07/02	These were at 18:26, 12/08/02	Lenticular clouds have been mistaken for UFO's. This particular cloud has the look of one of the ships in Independence Day (if you close one eye & squint that is) a close up is below, the image has lost some detail due to the digital zoom of the camera