Cyclone Alibera

Cyclone Alibera

Tropical cyclone (SWIO scale)
Category 4 (Saffir–Simpson scale)
Satellite image of Cyclone Alibera near peak intensity
Formed	December 16, 1989
Dissipated	January 5, 1990
Highest winds	10-minute sustained: 140 km/h (85 mph) 1-minute sustained: 250 km/h (155 mph)
Lowest pressure	954 hPa (mbar); 28.17 inHg
Fatalities	46 overall
Areas affected	Madagascar
Part of the 1989–90 South-West Indian Ocean cyclone season

Cyclone Alibera was the second longest-lasting tropical cyclone on record in the south-west Indian Ocean, with a duration of 22 days. It formed on December 16, 1989, well to the northeast of Madagascar. For several days, it meandered southwestward while gradually intensifying. On December 20, Alibera intensified to tropical cyclone status with 10‑minute maximum sustained winds of 120 km/h (75 mph), or the equivalent of a minimal hurricane. That day, the Météo-France office in Réunion (MFR) estimated 10‑minute winds of 140 km/h (85 mph), while the Joint Typhoon Warning Center (JTWC), an unofficial warning agency for the region, estimated peak 1‑minute winds of 250 km/h (150 mph). After drifting erratically for several days, the storm began a steady southwest motion on December 29 as a greatly weakened system. On January 1, Alibera struck southeastern Madagascar near Mananjary, having re-intensified to just below tropical cyclone status. It weakened over land but again restrengthened upon reaching open waters on January 3. The storm turned to the southeast, then to the southwest, and finally back to the southeast, dissipating on January 5.

Early in its duration, Alibera produced gusty winds in the Seychelles. Upon moving ashore in Madagascar, the cyclone lashed coastal cities with heavy rainfall and up to 250-km/h (150-mph) wind gusts. In Mananjary, nearly every building was damaged or destroyed, and locals considered it the worst storm since 1925. Across the region, the cyclone destroyed large areas of crops, thousands of houses, and several roads and bridges. Alibera killed 46 people and left 55,346 people homeless. After the storm, the Malagasy government requested for international assistance.

The first named storm of the season, Tropical Cyclone Alibera, formed on December 16 about halfway between Tromelin Island and Diego Garcia as a tropical disturbance. It originated from the Intertropical Convergence Zone and initially consisted of a spiral area of thunderstorms. The system moved erratically, first to the southwest, then to the southeast, and later curving back to the west, steered by a ridge to the southeast. On December 18, the Météo-France office in Réunion (MFR) estimated that the system attained winds of 65 km/h (40 mph), making it a moderate tropical storm. The MFR is the official Regional Specialized Meteorological Center for the basin. As a result, the Mauritius Meteorological Service named the storm Alibera. Also on December 18, the Joint Typhoon Warning Center (JTWC), a joint United States Navy and Air Force task force issuing cyclone warnings for the region, assessed that the storm had winds equivalent to a minimal hurricane in a post-storm analysis. While the storm was active, however, the JTWC did not begin advisories until the following day.