Severe Tropical Cyclone Ian

27 February - 3 March 1992

Summary

Ian was the second cyclone to be spawned during late February from an active southeast Indian Ocean monsoon trough. Ian was the first cyclone since Orson in April 1989 to cross the Western Australian coast.

Within two days of the formation of Harriet , another depression had developed in the mon- soon trough further east, approximately 300 km south of the southeastern tip of Java. Unlike Harriet , however, this system tracked eastwards in its early stages in response to a high amplitude upper trough located to the west. Enhanced upper divergence associated with sharpening of the trough assisted further development and at 1800 UTC 27 February, tropical cyclone Ian was named. Shortly afterwards, the upper trough weakened in association with an intensifying anticyclone over northwest Western Australia.

Ian consequently came under the influence of a deep-layer northerly steering current and it recurved to the south.

Ian continued to intensify within a favourable upper environment and by 0900 UTC 1 March had reached maximum intensity with mean winds estimated at 60 m/s. Although Ian began weakening as it approached the Western Australian coast, it was still a severe cyclone as it tracked directly over the Monte Bellos Islands and Barrow Island, where gusts to 57 m/s were recorded. Ian subsequently crossed a relatively uninhabited stretch of coastline approximately 75 km east of Onslow at 2145 UTC 2 March and weakened over land. Throughout Ian 's lifetime, ship observations, hourly satellite imagery and radar data ensured a high confidence in position location. In addition, the cyclone passed close to or over several reliable observation sites enabling the collection of a high-quality data set.

Impacts from tropical cyclone Ian were generally confined to the offshore islands. In the Monte Bellos group, a mining campsite was extensively damaged and a landing stage on Barrow Island sustained minor damage due to a 1.6 m storm surge.

Track and intensity

All times in WST - subtract 8 hours to convert to UTC.

Best Track of Severe Tropical Cyclone Ian