Date of Issue : 1 May 2018
Postmark : Whitemark TAS 7255
Denomination : 4 x AU$1.00
Stamp Size : 35 mm x 35 mm
Paper : Tullis Russell
Printing Process : Lithography
Clouds are made of tiny water droplets or ice crystals, suspended in the atmosphere. Every cloud belongs to one of the 10 main groups, called genera, each telling an important story about the physical processes taking place in the atmosphere. Most genera are further divided into species and varieties to account for differing characteristics. This stamp issue features different types of clouds or their features using dramatic photographs of cloud formations presented over three Australian states – the dramatic saucer-like clouds over Lachlan TAS, known as Lenticularis clouds; the hanging protuberances, like udders, on the under surface of a cloud, found near Booborowie SA, known as Mammatus clouds; clouds associated with atmospheric instability, like the lightning storm photographed between Auburn and Balaklava SA, known as Cumulonimbus clouds; as well as a low, horizontal formation appearing as a shelf or roll, found near Boonah QLD, known as Arcus cloud.