The low that subsequently became Harriet was first observed on 24 February embedded in the monsoon trough approximately 550 km east of Cocos Island. The low developed quite rapidly in association with a surge in the low-level cross-equatorial flow, and at 0600 UTC 25 February, the system was named. Initial movement of tropical cyclone Harriet was west-southwest towards the Cocos Island group, passing just south of North Keeling Island at 0000 UTC 27 February. Maximum mean winds were estimated to be 30 m/s at this stage and a peak gust of 45 m/s was recorded on Cocos Island, the second strongest on record (1952-92).
Continuing organisation of the cloud pattern occurred over the next 72 hours, and at 0000 UTC 1 March maximum intensity was achieved. At its most intense, Harriet was estimated to have sustained winds of 60 m/s and a central pressure of 930 hPa.
Harriet slightly weakened over the next three days whilst maintaining a steady westward course. An amplifying frontal system approaching from the west caused Harriet to recurve to the south during 4 March and begin to weaken under the effects of increasing environmental wind shear. By 0000 UTC 6 March the front was located about 15 degrees of latitude to the southwest of Harriet and an acceleration of the cyclone towards the southeast took place. Forward speed of movement of tropical cyclone Harriet increased to more than 30 m/s. The circulation centre passed 700 km to the southwest of Cape Leeuwin in southwest Western Australia during the evening of 8 March, shortly before losing warm-core characteristics.
Tropical cyclone Harriet was the second and most damaging cyclone during 1991-92 to affect the Cocos Islands. It caused minor residential property damage, mainly to roofing, and significant losses were sustained on horticultural land. Overall damage costs were estimated at $A60 000. There were no reports of injury.
Track and intensity
All times in WST - subtract 8 hours to convert to UTC.