Isobel was the ninth cyclone of the season, and like its immediate predecessor Helen, Isobel went through its life cycle without crossing land. However unlike Helen this cyclone did not nose a serious threat to communities in the northwestern part of Australia. At its closest approach to the continent Isobel was some 880 km to the west.
Satellite photographs and a small number of ship reports indicated that Isobel was a compact tropical cyclone of moderate intensity. Maximum winds close to the centre are estimated to have reached speeds of about 125 km/h on 12 and 13 March but the radius of gale force winds was probably no more than 130 km.
For more details see the TC Isobel Report (pdf).