Australian Weather Calendar: June 2020

June photograph by Michael Zupanc

On cloud nine

It seems when Mike Zupanc puts his mind to something, there's no stopping him. He recalls how he first got into flying gliders, which is how he came to photograph this spectacular morning glory cloud. 'Flying was something I'd always wanted to do, so I just went out and did it. A bit like photography, I just thought "what the heck?"'. While you'd normally find Mike photographing the local sports scenes in his hometown of Ipswich, Queensland, soaring the morning glory clouds that form near Burketown was always on his bucket list. 'As that cloud moves along it generates a big area of rising air in front of it, so once you're up in the air you can turn the engine off and just ride the waves of the cloud—a bit like a surfer surfing an ocean wave,' he says. Mike describes soaring the morning glory cloud as 'an incredible feeling' and says that he's already making plans to do it again. Knowing Mike, it won't be too long before he's back on cloud nine!

The science

The 'morning glory' is a type of roll cloud which can be many hundreds of kilometres long. They're generally rare, however they occur reasonably consistently across the Gulf of Carpentaria from September to November, with several normally forming during this period.

The cloud is usually formed, in the right conditions, by the interaction between sea breezes on both sides of Cape York Peninsula, which results in a line of cloud. As night falls, the air over land cools and descends while an inversion (a stable layer of air where temperature increases with height) forms over the water in the gulf. The descending air from the peninsula slips under the inversion layer and generates a series of waves which move across the gulf. At the head of each wave, water vapour in the rising air condenses to form cloud, while at the back it evaporates as it descends—forming the roll cloud.