1999–2000 South-West Indian Ocean cyclone season
The 1999–2000 South-West Indian Ocean tropical cyclone season was the first on record in which two storms – Leon–Eline and Hudah – struck Mozambique at tropical cyclone intensity, or with maximum sustained winds of at least 120 km/h (75 mph). The most notable storm of the season was Eline, which was the longest-lasting storm on record in the basin. It lasted for 29 days while traversing the southern Indian Ocean, making the strongest landfall in decades along eastern Madagascar in late February. The storm was the first in a series of three storms that struck the country in early 2000, along with Gloria in March and Hudah in April. Collectively, the three storms killed at least 316 people. The season started on November 1, 1999, and ended for most of the basin on April 30, 2000; for Mauritius and the Seychelles, the season continued until May 15. These dates conventionally delimit the period of each year when most tropical cyclones form in the basin;
1989–90 South-West Indian Ocean cyclone season
A tropical depression developed within the monsoon trough on February 2 to the southwest of Diego Garcia, about east of Cezura. The JTWC had been tracking the system for several days previously, classifying it as Tropical Cyclone 16S also on February 2. With an anticyclone – a high pressure area over the system – providing favorable conditions, the depression quickly intensified while moving generally south-southwestward. It became Moderate Tropical Storm Dety on February 3 and a tropical cyclone the next day. The MFR estimated peak 10‑minute winds of , while the JTWC assessed stronger 1‑minute winds of 175 km/h (110 mph). Around that time, Dety began a Fujiwhara interaction with Tropical Storm Cezura to the west, causing the former storm to turn to the east-southeast. Increased wind shear weakened the cyclone, although it maintained much of its intensity through February 7 as a severe tropical storm. However, Dety quickly fell to tropical disturbance status the next day while undergoing a counterclockwise loop. After turning back to the southeast, Dety remained a weak system for several days, dissipating on February 11.