Fig. 7 Contrast of observed IH* tracks between 1950 and 1991 from the ten most active hindcast (IH* > 2.5 and IHD* > 5.2) seasons versus the ten calmest hindcast seasons (IH* < 1.1 and IHD* < 1.1). The IHD* ratio of this difference is 12.9 to 1.