High Quality Content by WIKIPEDIA articles! The 1990–91 Australian region cyclone season was an average cyclone season, with ten tropical cyclones occurring within the region between 90°E and 160°E. The season officially ran from November 1, 1990, to April 30, 1991 with the first disturbance of the season forming on 10 December and the last disturbance moving out of the region during 11 May. Six people were killed by Cyclone Joy when it made landfall on Australia. During the season, tropical cyclones were monitored by the Australian Bureau of Meteorology, who ran Tropical Cyclone Warning Centers (TCWC) in Perth, Darwin, and Brisbane. The United States Joint Typhoon Warning Center (JTWC) and Papua New Guinea National Weather Service also monitored systems within the basin during the season. The JTWC designated systems with a number and either a S or a P suffix depending on which side of 135E. The Bureau of Meteorology and Papua New Guinea national Weather Service both used the Australian Tropical Cyclone Intensity Scale, and estimated windspeeds over a ten minute period, while the JTWC estimated sustained winds over a one minute period and are comparable to the Saffir–Simpson Hurricane Scale.