This system formed southeast of the Seychelles on January 7 before becoming disorganized while interacting with northern Madagascar. The system redeveloped as a hurricane-force cyclone in the northern Mozambique Channel on January 16 before moving southeast into Madagascar on January 19.[1]
The origins of Cyclone Gervaise were in early February 1975 from a circular area of convection, or thunderstorms, located in the Intertropical Convergence Zone southwest of Diego Garcia in the south-west Indian Ocean. The system organized as it moved generally to the southwest, a trajectory it would maintain for several days due to a subtropical ridge to its southeast, and an area of low pressure near the Mascarene Islands. On February 2, the Mauritius Meteorological Services[a]named the stormGervaise. Two days later, the storm attained hurricane status, or maximum sustained winds of at least 120 km/h (75 mph).[3] Late on February 5, Gervaise passed about 100 km (60 mi) southeast of St. Brandon. Continuing southwestward, the cyclone struck Mauritius on February 6, with the calm of the eye lasting for three hours. That day, the American-based Joint Typhoon Warning Center (JTWC)[b] estimated peak winds of 130 km/h (80 mph).[4] On February 7, Gervaise passed about 130 km (80 mi) southeast of Réunion. The track shifted to the south and southeast over time, steered by a passing cold front. On February 10, Gervaise dissipated within the cold front.[3]
Gervaise first affected St. Brandon, producing wind gusts of over 100 km/h (62 mph), along with heavy rainfall. Cyclone Gervaise killed 10 people during its passage of Mauritius. Its strongest wind gusts occurred after the passage of the eye, peaking at 280 km/h (170 mph) at Mon Desert. Heavy rainfall affected the island for several days, reaching 674 mm (26.5 in) at Grosse Roche. The high winds knocked down power lines, radio transmission with Vacoas for 24 hours, and many crops. About 25% of the island's sugar cane crop was lost. The storm damaged several houses, leaving thousands homeless. The cyclone last affected Réunion, where it produced wind gusts of 180 km/h (110 mph). Gervaise also dropped heavy rainfall on the island, reaching 548 mm (21.6 in) at Plaine des Cafres.[3] It caused substantial damage to properties, vegetation and wildlife. Moored yachts around the coast were washed hundreds of yards inland in places due to the storm surge and in the Mauritian capital Port Louis, a cargo ship of ca. 10,000 tonnes was washed up on to the quay. 34 injured, 3,706 homeless.
^The Joint Typhoon Warning Center (JTWC) is a joint United States Navy – United States Air Force task force that issues advisories for storms in the basin.
^ abcHurricane Gervaise, 1–9 February. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved February 3, 2019.
^Kenneth R. Knapp; Michael C. Kruk; David H. Levinson; Howard J. Diamond; Charles J. Neumann (2010). 1975 Tropical Cyclone Gervaise (1975033S11073). The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data (Report). Bulletin of the American Meteorological Society. Retrieved February 3, 2019.
