Australian Weather Calendar: October 2016
Roll clouds form consistently in the Gulf of Carpentaria around September–October. At night, air over Cape York Peninsula cools and descends, while over the gulf an ‘inversion layer’ forms, in which temperature increases with height. Descending air from the peninsula slips under this layer to form waves that move across the gulf. At the head of each wave, water vapour in the rising air condenses, forming cloud, then evaporates at the back as it descends.
You can see these ‘morning glory’ clouds coming from quite far away, says Tex Battle, owner of the Sweers Island resort; ‘you’ve got at least 45 minutes notice’. On 23 August 2009, a friend flew Tex up in single-engine Cessna aircraft to 'surf' along the front of the wave, while Tex took photos. ‘Sometimes there’ll be three or more clouds,’ says Tex, ‘one behind the other… but the front one’s always the best.’
Tex was using a Fujifilm FinePix.