by Hugues Goosse
Antarctica is often referred to as the windiest continent on Earth for several reasons. First, there is not many obstacles at surface like hills, buildings or trees that can slow down the winds. Second, even though large portions of the continent are flat, some regions experience large slopes that can be followed by intense winds. Finally, large temperature contrasts can induce large pressure difference and thus strong winds, at a different scale but in a similar way as in air flows in your house.
The strongest winds, called katabatic winds, occurred in coastal regions. The air in the interior of the continent, where the altitude of the surface is high, is very cold, and thus very dense. This dense air may literally flow down the slope towards the coast because of the gravity, accelerating until it reaches very high velocities.
Those winds can achieve velocities higher than 200 km/h. They are so strong that, even in winter, they can transport all the sea ice floating at the surface of the ocean away from the coast as soon as it is formed, leaving the ocean ice free even though the air temperature is -20°C.
Fortunately for us, katabatic winds very rarely occurs in summer close to the station and at our measurement sites. Nevertheless, the winds can still be very strong, blowing large amount of snow over long distances.
Vidéo taken in 2017 by Jean-Louis Tison of katabatic winds in the Ross Sea
Vidéo taken by Nander Wever during the storm that hit us at Novo station