The 2001–02 South-West Indian Ocean cyclone season had the earliest named storm since 1992. Many storms formed in the north-east portion of the basin, and several more originated around Australia. The basin is defined as the waters of the Indian Ocean west of longitude 90°E to the coast of Africa and south of the equator. Eleven tropical storms formed, compared to an average of nine. Tropical systems were present during 73 days, which was significantly higher than the average of 58 for this basin.
Tropical cyclones in this basin are monitored by the Regional Specialized Meteorological Center (RSMC) in Réunion. The season started on November 1, 2001, and ended on April 30, 2002; 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; however, storms formed both before and after the designated season. The first storm was Andre, which emerged from the Australian basin as Tropical Cyclone Alex in late October. The strongest storm, Cyclone Hary, was the first very intense tropical cyclone since 2000; it hit Madagascar, where it caused lighter damage than expected but three deaths. In January, Cyclone Dina left heavy damage in the Mascarene Islands, particularly on Réunion, where it dropped of rainfall. The second-to-last storm was Cyclone Kesiny, which killed 33 people when it struck Madagascar in the midst of a political crisis. __TOC__
Season summary
Météo-France's meteorological office in Réunion (MFR) is the official Regional Specialized Meteorological Center for the South-West Indian Ocean, tracking all tropical cyclones from the east coast of Africa to 90° E. The Joint Typhoon Warning Center (JTWC), which is a joint United States Navy – United States Air Force task force that issues tropical cyclone warnings for the region, also issued advisories for storms during the season. Following the season, the start of the tropical cyclone year was changed to July 1, which defines the boundary between tropical cyclone seasons.
Although the previous season was tame, the 2001–02 season was very active and featured several intense tropical cyclones. During the season, eleven systems were named, which was slightly above the average of nine. However, nine of the systems attained cyclone intensity, the second highest total in 30 years. In terms of both the number of systems and number of "cyclone days", the season was considered comparable by MFR to the 1993–94 season. In this season, there were 73 days on which tropical cyclones were active, which was more than twice as much as the previous season and 19 days above the average. A system of cyclone intensity was active on 35 days, which was 15 days above the mean. Additionally, five of the systems attained "intense tropical cyclone" status, including one – Hary – that attained the "very intense tropical cyclone" stage. Activity was relatively distributed throughout the season and had the earliest start since 1992. Like most seasons within the basin, activity reached a climax in late January. Several systems during the season developed in the eastern portion of the basin, similar to 1993–94; unlike that season, many storms in 2001–02 stayed at sea throughout their lifetime, thus reducing casualties and damage.
Systems
Tropical Depression 01
The first storm of the season originated from an area of convection east of Diego Garcia in early October 2001. Moving southwestward, it slowly organized, with convection developing around a weak circulation. Late on October 3, MFR classified the system as a zone of disturbed weather. On October 5, the agency re-classified it as a tropical disturbance and later as Tropical Depression 1. The circulation was partially exposed due to wind shear, although it had good outflow. The JTWC initiated advisories on Tropical Cyclone 01S at 0600 UTC on October 6, estimating winds of about . Due to the shear, the convection gradually diminished, prompting the MFR to downgrade it to a tropical disturbance on October 7. The next day, the JTWC issued its last advisory, noting that the system was dissipating.
Severe Tropical Storm Alex–Andre
The Bureau of Meteorology (BoM) classified a tropical low as Tropical Cyclone Alex on October 26 in the Australian region. It was initially located in an area of strong wind shear, which prevented significant strengthening. However, convection over the system increased on October 27, and it crossed into the South-West Indian Ocean at around the same time. It was renamed Andre, becoming the earliest date for the first named storm since 1992. After reaching 10‑minute sustained winds of , according to the MFR, Andre began slowly weakening, due to increasing shear. It moved generally to the west-southwest before turning northwestward on October 29, around which time the convection separated from the center. Moving slowly, Andre later turned to the southwest after weakening to a tropical depression. Late on October 31, the system was no longer classifiable as a tropical system, and the remnants continued to the west-southwest until being absorbed by a trough on November 8.
Tropical Depression 03
A zone of disturbed weather formed on November 15 in the eastern part of the basin. It remained a zone of disturbed weather for a few days before briefly strengthening into a tropical depression on November 21. It dissipated two days later. This system was also designated as tropical cyclone by the JTWC.
Tropical Cyclone Bessi–Bako
The monsoon trough spawned a tropical low on November 24 in the Australian basin. It moved to the southwest, strengthening into Tropical Cyclone Bessi on November 27. Two days later, it moved into the South-West Indian Ocean, and was renamed Bako on December 1. Located in a similar position to the previous storm, Bako strengthened into a severe tropical storm on December 1, aided by warm waters and slack wind shear. The storm turned to the southeast on December 2, despite predictions to the contrary, and later that day it intensified further into a tropical cyclone, the first of the season. However, on December 3, Bako weakened back into a severe tropical storm due to much cooler sea surface temperatures and increasing northwesterly wind shear. It weakened into a tropical depression on December 5, before transitioning into an extratropical cyclone the same day. RSMC La Reunion continued to track the remnants of Bako until December 9.
Severe Tropical Storm Cyprien
On December 25, a cold front dragged over the central Mozambique Channel. A weak circulation formed in the Channel and moderate convection appeared on December 27. Then on December 30, RSMC La Reunion designated this low pressure as a zone of disturbed weather and was classified as a tropical depression on January 1, 2002. The JTWC also issued a Tropical Cyclone Formation Alert (TCFA) early on December 31 and designated it as Tropical Cyclone 08S the next day. As it moved further eastwards it strengthened quickly from a tropical depression into a severe tropical storm, with the Meteorological Services of Madagascar giving it the name Cyprien on January 1. Cyprien soon became a serious threat to western Madagascar. Convection began to dissipate as wind shear increased and that resulted in quick weakening to a tropical depression. As it made landfall on western Madagascar, it dropped heavy rainfall. In all, Cyprien destroyed 841 homes in the towns of Morombe and Morondava. Damage in the towns was estimated at $180,000, but there were no deaths.
Intense Tropical Cyclone Dina
Cyclone Dina originated in a tropical disturbance first noted on January 15 near the Chagos Archipelago. By January 17, the system had developed enough organized convection as it moved southwestward to be declared a tropical depression. Rapid intensification occurred shortly thereafter, with the system attaining winds in excess of on January 18. Dina peaked in intensity on January 20 as an intense tropical cyclone with winds of . Hours later, the storm bypassed Rodrigues Island about to its north. On January 21, the storm brushed Mauritius and Réunion as an intense tropical cyclone before turning southward. Once on a southward course, steady weakening ensued and the system eventually transitioned into an extratropical cyclone on January 25. The remnants of the storm accelerated southeastward and were absorbed into a polar trough on January 28.
Across Mauritius and Réunion, torrential rains and destructive winds from the cyclone resulted in extensive to "catastrophic" damage. The entire island of Mauritius lost power during the storm and widespread structural damage took place. Agricultural and property damage amounted to US$47 million and US$50 million respectively in the republic. Nine fatalities were attributed to the storm in Mauritius: five off the coast of Rodrigues Island and four on the main island. More extensive damage was seen on Réunion where up to of rain fell over three days. Flooding destroyed many homes, washed out roads, and caused catastrophic agricultural damage. Destructive winds, measured at up to , also crippled communications. In all, six people died on the island and losses were estimated at €200 million (US$190 million).
Tropical Cyclone Eddy
A system developed within a convergence zone on January 20 near the boundary between the South-West Indian Ocean and the Australia region. Its circulation became better defined, and MFR initiated advisories on January 22. With a ridge to the south, it drifted to the southeast, approaching 90°E, but turning to the southwest before crossing over. On January 23, the system intensified into a tropical depression. Slowly intensifying, the depression became Tropical Storm Eddy on January 24. That day, the JTWC initiated advisories on Tropical Cyclone 11S, and it turned toward the south. After having experienced moderate wind shear, Eddy entered an area of more favorable conditions, and its convection gradually organized. Early on January 26, MFR upgraded it to a tropical cyclone, later estimating peak winds of . After that time, increasing wind shear weakened Eddy to a tropical storm, causing it to curve to the west. By January 28, the circulation was exposed from the convection, and Eddy weakened to a tropical depression. It turned to the southwest the next day, and dissipated fully on January 30.
Intense Tropical Cyclone Francesca
The origins of Francesca were from a tropical low that formed in the Australia region on January 28, east of the Cocos Islands. This was near the same place that Eddy had formed a week prior. The system that became Francesca moved west-southwestward due to a ridge to the south. On January 30 it crossed into the South-West Indian Ocean, where wind shear prevented significant development. On January 31, the system intensified into a tropical depression, and late the next day the JTWC classified it as Tropical Cyclone 12S. Wind shear diminished on February 2, which allowed the depression to strengthen into Tropical Storm Francesca after convection increased. It continued to intensify steadily, becoming a tropical cyclone on February 3. The next day, the JTWC upgraded Francesca to the equivalent of a minimal hurricane.