The record windstorm event at Casey Station, Antarctica, 5–6 January 2022

On 5–6 January 2022, a deepening cyclone approaching the coast of east Antarctica brought a vigorous downslope windstorm and prolonged blizzard conditions to Casey (66.28°S, 110.52°E), an Australian research station in Antarctica. Sustained storm-force winds persisted for ~24 h, and the maximum gust of 213 km h–1 (59.2 m s–1 or ~115 knots) set a new January wind gust record for the station. As the cyclone approached the Antarctic coast, the system caused a broad-scale warm-air advection over the Casey–Law Dome area and strengthened an easterly jet in the low-level atmosphere, resulting in the formation of bullet-shaped wind profiles. This distinctive upwind aerological structure, together with the interaction between the low-level jet and the topography of Law Dome, facilitated the development of wave breaking, flow transition and a hydraulic jump over moderate topography. These mesoscale processes are identified as the main mechanisms responsible for the downslope acceleration of the flow that produced the record windstorm at Casey.