| Above: Visible MODIS image of Tropical Cyclone Cilida taken on Friday afternoon, December 21, 2018. Image credit: NASA. |
Category 4 and 5 storms in the South Indian Ocean are rare in December, which is the beginning of their tropical cyclone season. The Southern Hemisphere tropical cyclone season peaks in March, when ocean temperatures are at their warmest. Only one Category 5 storm has been observed in December in the South Indian Ocean—Tropical Cyclone Bruce, which topped out with 160 mph winds on December 21, 2013.
3 belles images du #cyclone tropical intense #CILIDA par https://t.co/7rwFUMLjet pic.twitter.com/Cgw3RCQi2A
— L'œil du cyclone (@Firinga_le_site) December 21, 2018
Strongest storm in the South Indian Ocean since Category 5 Marcus in March
Since accurate satellite records began in 1990, the Joint Typhoon Warning Center has catalogued 18 Category 5 storms in the South Indian Ocean—an average of approximately one Cat 5 every two years. Marcus was the first Category 5 tropical cyclone in the South Indian Ocean since Tropical Cyclone Ernie, which intensified to a Category 5 storm with 160 mph winds northwest of Australia in April 2017.
Tropical Cyclone Fantala of 2016 (180 mph winds) is the strongest cyclone ever observed in the South Indian Ocean. Fantala is also the all-time intensity record holder for the entire Indian Ocean, since it tops the record holder for the North Indian Ocean, Super Cyclonic Storm Gonu of June 2007 (peak 1-minute winds of 165 mph). Note, though, that some consider Tropical Cyclone Monica of 2006 (180 mph winds) tied as the strongest Indian Ocean Basin storm on record. Definitions vary on the boundary of the Indian Ocean, though, and Monica reached peak strength north of Australia in the Arafura Sea, which is considered by several sources, including the CIA World Factbook, to be part of the western Pacific Ocean, not the Indian Ocean.
