Incredible photographs showing Australia's weather changing over the course of the year have been released. Featuring a dust devil, a fallstreak hole and a fogbow, the images are part of the Bureau of Meteorology's (BoM's) 2016 Australian Weather Calendar.
The photos selected for the calendar were whittled down from over 800 entries. The cover image shows dark clouds over sand dunes near Mungo in New South Wales, captured by photographer Tony Middleton.
"I noticed the convection develop 50 kilometres north west of our location," he said. "Determined to catch it, I made my way through 30 kilometres of four-wheel-drive tracks, and scaled multiple sand dunes to this ridge line to arrive just in time as the storm hit, and proceeded to dump rain, thunder and lightning."
Vicki Middleton, deputy director of corporate services for the BoM, said: "This multi-award-winning calendar provides a platform for the Australian community to connect with their environment through the art of photography, while serving as an educational resource on our unique weather and climate."
Liam Byrne spotted this fogbow while driving across Tasmania in winter 2010. He had packed his camera, as he was taking the ‘scenic route’ past Great Lake, but adds, "Everywhere in Tassie is a nice drive." BoM Jacob Elliot was chasing a storm near Mt Bryan in South Australia, 7 January 2015, hoping to take some photos of the lightning. When he looked back towards Burra and saw a towering dust devil, his objective changed. BoM On 27 April 2012, Tony Derix was camping in Menindee Lakes, New South Wales, on the bank of Lake Pamamaroo. "The night before that the light was really good, so I set myself up on that spot for the sunset, and it turned out to be a magnificent sunset," he recalls. BoM Working for a ground handling company at Sunshine Coast Airport in 2008, Shane Loweke was on the tarmac waiting for an aircraft when he saw a shelf cloud loom in from the southwest. BoM In December 2008, in outback South Australia, Graham Nicholls saw his first dust storm—from closer than he’d planned. From where he was staying at Umuwa, the administration centre for the Anangu Pitjantjatjara Yankunytjatjara lands, Graham saw the sky turn a weird red colour. "I thought I’d just grab the camera and go for a drive. I drove out to the airstrip and I was confronted by that wall of dust; so I just kept clicking away, and eventually I left my run too late and got caught up in it. I started driving back to the donga and it was like someone just turned the lights out," he says. BoM Casper Smit is a chemical engineer, and has spent the past four years working in magnetite mines around Western Australia. Near one mine east of Mount Magnet, in August 2014, Casper noticed thin, wispy clouds known as cirrus clouds. They are formed by ice crystals, high up in the atmosphere. Cirrus clouds often move along in a high, fast-flowing wind known as a jet stream, which crosses Australia from west to east. BoM David Barton and his wife spotted a rare phenomenon over eastern Victoria on 3 November 2014. Fallstreak holes, or hole punch clouds, form in clouds that contain supercooled water droplets—at a temperature below freezing point, but not frozen. A trigger such as a passing aircraft causes ice crystals to form, and a chain reaction makes water droplets around those crystals evaporate, leaving a ‘hole’ around the wispy patch of ice crystals. BoM Frost is a deposit of soft white ice crystals or frozen dewdrops, formed when a surface is below both freezing point and the ‘dew point’ at which moisture condenses from surrounding air. Frost formation is affected by cloud coverage, humidity, surface winds, topography and location. In Australia, frost is more likely under a clear sky, with low humidity and light surface winds. BoM Kurt Ams often takes photos from the top of his apartment building in Mascot, New South Wales (south of Sydney’s CBD), but had never seen a cloud like the bubbling formation overhead on 16 September 2014. He called a friend at nearby Sydney Airport, who confirmed it was a mammatus cloud. BoM 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. BoM Rainbows form when sunlight is refracted (bent) and reflected by raindrops: Blue light refracts at a greater angle than red light, separating the colours. From the ground, you can only see light refracted through drops above you, so you see the familiar semi-circular rainbow. Colin Leonhardt, in a helicopter with the sunset behind him and a rain shower ahead, saw refracted and reflected light from both above and below—forming a full circular rainbow. BoM The Australian tropics experience two distinct seasons—‘dry’ from May to September and ‘wet’ from October to April. As the end of the year approaches, temperatures increase in tropical areas and a shift in the prevailing wind direction brings increased moisture into the area from warm oceans over the Arafura Sea to Australia’s north. "At that part of the build-up," says Darwin local Cathryn Vasseleu, "Up until about December, there’s really big lightning storms but it’s not raining—so you can get photos of big lightning strikes because you’re not in peril of being drenched. Where I took the photo is a popular spot that people actively come to view the lightning. Up here, lightning is almost a way of life," adds Cathryn, "It’s part of the pleasure of the build-up to the wet season." BoM