October: Warning sky materialises for West Australian aviator

Few people know Western Australia’s vast landscapes as well as Tony Robinson. For seven years he was a pilot with the Royal Flying Doctor Service, operating out of Port Hedland and Carnarvon, and is now a flight operations inspector for the Civil Aviation Safety Authority. Tony has also worked out of more than 30 major and minor airports, always with a camera ready in the cockpit or the car. This routine paid off late one afternoon in December 2004 when thunderstorm clouds appeared over Derby airport in northwest WA. The mammatus clouds, associated with a deepening trough or front, loomed briefly “out of nowhere” from the base of the storm cloud directly over the small terminal.

Mammatus clouds generally appear at the base of cumulonimbus (thunderstorm) clouds and indicate strong movement of air. Their characteristic appearance is due to cold pouches of the cloud descending into warmer and vigorously rising or falling air. The strong vertical movement — particularly dangerous for aviation — is due to large differences in air temperature, moisture and movement at different levels of the atmosphere.

Note: The photograph in the printed calendar is NOT watermarked with a copyright symbol and name.

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