- 270 kilometre(s) per hour
- Antarctica ()
Katabatic winds are caused by cold, dense air from high altitude flowing downhill under the force of gravity. The fastest winds of this type are found around the coastal escarpment of Antarctica. Writing about the 1911–14 Australasian Antarctic Expedition in The Home of the Blizzard (1915), British-Australian geologist and explorer Douglas Mawson – who led the expedition – described experiencing estimated instantaneous wind speeds in excess of 75 metres per second (270 kilometres per hour; 168 miles per hour) at Cape Denison in Commonwealth Bay, Antarctica.
On 24 March 1912, Mawson recorded an hourly wind speed of 48.9 m/s (176 km/h; 109 mph); though later studies have adjusted this down to 41.6 m/s (149 km/h; 93 mph).
Based on more recent data, the fastest katabatic wind speed (representing a 10-minute average) was measured by high wind speed sensors deployed as part of the AWS (automatic weather station) instrumentation at Cape Denison in 1995, where gusts in excess of 57 m/s (205 km/h; 127.5 mph) were recorded.
Because they are driven by geography, katabatic winds are known for their consistency of direction.