Australian Weather Calendar
June: Hail fellow, well Met
No surprise that a Meteorologist (often abbreviated 'Met') should exult when his storm chasing north of Bendigo in central Victoria leads him to an unusual landscape of hail around 15 cm deep. Melbourne University PhD student John Allen, something of a serial storm chaser who has been four times to 'Tornado Alley' in the American Midwest and has chased all around Australia, had never previously seen anything like the volume of hail he came across in the wake of a thunderstorm at Marong on 22 October 2011.
Always seeking a different picture, he was thrilled when the sun came out, with little hail fog, and he found a gap between the trees. 'The ice was very wet and very cold to lie on, as the temperature had dropped 12 degrees due to the hail, but it was definitely worth the pain to get the shot,' he says. 'Trying to get a low angle, I rested the both the camera and myself on the ice. Fortunately we both made it out with no obvious damage.' Now living in Templestowe, Melbourne, John has been interested in photography since childhood. Experiencing a series of intense hailstorms in Sydney during the 1990s helped him settle on a thesis examining the potential impacts of climate change on severe thunderstorm environments in Australia.
Hail forms when very cold water droplets in clouds collide with ice particles and freeze on impact. This process continues until the hailstone is heavy enough to fall to the ground, overcoming the cloud's updraft. Stronger updrafts, such as those in severe thunderstorms, allow more water droplets to freeze onto the hailstone, producing larger hail.