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Cyclone Gretelle

South-West Indian tropical cyclone 1997

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Through International Red Cross and Red Crescent Movement and United Nations

Damage from Cyclone Gretelle was heaviest near where it made landfall in Madagascar. In several villages, over 90% of the buildings were destroyed, leaving about 80,000 people homeless. Wind gusts at Farafangana reached 220 km/h (140 mph), which knocked trees onto roads and wrecked about 138,000 tons of crops. Heavy rainfall and high waves flooded coastal regions, in some areas up to 16 m (52 ft) deep. Overall damage was estimated at around $50 million, and there were 152 deaths. After the storm, there was a coordinated international relief effort to provide food and money to Madagascar.

Meteorological history

The Intertropical Convergence Zone spawned a tropical disturbance on 19 January, developing a circulation just west of St. Brandon. That day, the Météo-France on Réunion (MFR) classified the system as a tropical disturbance, and the Joint Typhoon Warning Center (JTWC) began monitoring the system as a low-pressure area a day prior. The system intensified into Tropical Storm Gretelle late on 20 January, by which time the JTWC gave it the designation Tropical Cyclone 20S. Due to a large ridge centered near Île Amsterdam, the storm tracked generally southwestward toward the Mascarene Islands. Early on 22 January, the JTWC upgraded the storm to the equivalent of a minimal hurricane, and later that day, the MFR upgraded Gretelle to tropical cyclone status, or with 10-minute sustained winds of at least 120 km/h (75 mph).

Shortly after attaining tropical cyclone status, Gretelle made its closest point of approach to Réunion late on 22 January, passing about 300 km (190 mi) northwest of the island. Subsequently, the cyclone developed a small eye, and the MFR estimated peak 10-minute winds of 140 km/h (85 mph) at 0000 UTC on 23 January. Meanwhile, the JTWC estimated Gretelle continued to intensify to a 1-minute sustained wind peak of 215 km/h (135 mph) at 0600 UTC on 24 January, equivalent to a Category 4 hurricane on the Saffir–Simpson scale. Later that day, the cyclone made landfall on southeastern Madagascar near Farafangana near peak intensity. Reports from the United Nations Department of Humanitarian Affairs considered Gretelle the first cyclone to strike the region in 41 years. Gretelle rapidly weakened over land, emerging into the Mozambique Channel as a tropical depression on 25 January. Continuing to the southwest, the depression re-intensified into a tropical storm on 27 January.

After becoming a tropical storm again, Gretelle slowed in the Mozambique Channel. A cold front bypassed the storm to the south, and a building ridge behind it turned Gretelle to a west-northwest drift. Although it approached southeastern Africa on 28 January, an advancing trough turned the storm to the southeast. The next day, the JTWC briefly re-upgraded Gretelle to the equivalent of a minimal hurricane, and on 30 January, the MFO estimated a secondary 10-minute wind peak of 85 km/h (55 mph). Accelerating to the south-southeast, Gretelle dissipated on 31 January well to the south-southwest of Madagascar.

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