Cirrus Clouds

Cirrus clouds are high level clouds at an altitude in excess of 6,000 metres (20,000ft). At this altitude the condensing water vapour usually forms tiny ice crystals. These clouds often look like "wisps or curls of hair, hence their name "Cirrus". They are usually a phenomena of good weather appearing only in a stable atmosphere.

At dawn and dusk light from the sun reflecting upon these cloud formations often produces spectacular and colourful displays. Similarly refracted light from the sun, or even the moon, may cause other interesting optical effects such as "coronas".

Alto Clouds

These are mid level, between 2,000 and 6,000 metres (6,500 and 20,000ft), cloud formations where the condensing water vapour usually remains as water droplets but ice crystals can form when the temperature is low enough.

Cumulus Clouds

With their base below 2,000 metres (6,500ft) these clouds are usually composed of water droplets but once again when temperatures are low enough they made contain particles of ice and/or snow. Formation of Cumulus clouds is associated with an unstable atmosphere. Scattered formations of Cumulus clouds are often called "shower clouds" whereas formations of Cumulostratus are often provide "rain clouds" and are prevalent when the sky is "overcast" or completely obscured by cloud.

Cumulo-Nimbus

These vertical cloud formations are usually associated with thunder storms and storm cells.

Lenticular Cloud Formation

These clouds are formed due to wind current lifting moisture laden air over mountain tops. They can also form as a result of air waves moving of hilly or undulating terrain.

Banding

Vapour Trails or Contrails

These are created as a result of the water vapour in the exhaust gases of jet engines freezing and forming ice particles at high altitude.

The narrow trail  is eventually spread out and dispersed by the wind.