A rare thundersnow event hit the Blue Mountains, west of Sydney, Australia, over the weekend.
Thundersnow is a natural phenomenon that occurs when snow falls during a thunderstorm instead of rain.
“You get the bang and the rumble but instead of it being dominated by rain and hail, it’s all snow that’s coming out of the system,” Mick Logan, the Bureau of Meteorology forecaster said, according to the Sydney Morning Herald.
— news.com.au (@newscomauHQ) July 11, 2015
“There’s usually a bit of hail that comes with it as well,” he said. “It happens when the atmosphere is so cold that instead of getting rain, the bulk of the precipitation is snow.”
The phenomenon of thundersnow is very rare, and Logan says he has never heard of it occurring in the Blue Mountains.
“We don’t keep records of them at the bureau so it’s hard to know how often we get them,” he said. “It’s fairly unusual to get the ingredients for a thunderstorm when the atmosphere is cold enough and is really only going to be producing snow.”
— 7 News Sydney (@7NewsSydney) July 12, 2015
Convection, the upward motion of air, helps to produce thunderstorms. However, it is incredibly rare to have convection with winter storms, making thunder and lightning much more common with warm weather storms, according to dbtechno. When there is strong convection, mixed with extreme moisture in the air, thundersnow can occur. When thundersnow does occur, it typically brings heavy accumulation that can hinder viability. While the thunder may be muffled, the lightning associated with thundersnow is clearly visible.
— Canberra Times (@canberratimes) July 12, 2015
The snow was continuing to fall into the Sunday hours. Several residents in the area uploaded pictures of the accumulated snow to social media.
— Angela Barlow (@excelsior7) July 11, 2015
— Sarah (@twinbumps) July 11, 2015
[Photo via Shutterstock]