During the past week at Casey, Mother Nature has provided us with some pretty spectacular weather phenomena. We were firstly blessed with a ‘sun dog’ or scientific name ‘parhelia’. Sun dogs consist of glowing spots around the sun that are created by sunlight refracting off plate shaped ice crystals in cirrus clouds. Sun dogs tend to be most visible when the sun is close to the horizon.
Frost was the second phenomena that we observed during the past week at Casey. Frost forms when an outside surface cools past the dew point. The dew point is the point where the air gets so cold, the water vapour in the atmosphere turns into liquid. This liquid then freezes. If it gets cold enough, little bits of ice, or frost, form. Obviously here in Antarctica the ‘if it gets cold enough’ part of that explanation doesn’t really apply, so on Tuesday when a thick fog rolled in to station, all of the moisture in the air froze and the station turned into a bit of a winter wonderland where everything was coated in ice crystals providing some pretty impressive photo opportunities.