Australian Weather Calendar: September 2020

September photograph by Andrew Thomas

Journey through the fog

As a former marathon runner, Andrew Thomas certainly knows that persistence pays off, and the same could be said for his photography. Over many years he's honed his craft, embracing the latest drone technology, and working tirelessly on two major projects—photographing the 59 USA national parks, and photographing his local district around Ballarat, Victoria, within a 42 km boundary (42 km being marathon distance, of course!). The latter project has seen him become somewhat of an expert in fog photography—in fact, his images of fog have won him a place in the Australian Weather Calendar for the third year in a row! 'I've become pretty good at judging the fog around the district,' Andrew says. 'On this particular morning I was flying the drone and the conditions were just perfect with the sun filtering through the fog. Then in the distance I heard the whistle of the train, and so I hovered for a minute or two and grabbed the shot as it passed over the bridge.'

The science

Fog is formed when water vapour condenses into tiny droplets of liquid water suspended in the air. Fog often forms in valleys as air that has been cooled at higher elevations sinks downslope into the valley. The temperature on the valley floor decreases with the arrival of the cold air, and water vapour condenses, forming fog. Generally fog begins to clear after sunrise, as the radiation from the sun heats the air and evaporates the water droplets.