Intense Tropical Cyclone Leon–Eline was the second longest-lived cyclone in the Indian Ocean, behind Cyclone Freddy, traveling over 11,000 km (6,800 mi) during its 29-day track through the Indian Ocean, throughout the month of February. The cyclone formed on 1 February 2000, in the Australian basin as Tropical Cyclone Leon, and was renamed Eline after crossing 90° E into the South-West Indian Ocean; there, the Météo-France office in Réunion (MFR) tracked the storm's movement and intensity. Late on 17 February, Eline made landfall near Mahanoro, Madagascar, with 10‑minute winds of 165 km/h (103 mph). The storm rapidly weakened over land, but restrengthened in the Mozambique Channel to reach peak 10‑minute winds of 185 km/h (115 mph), making it an intense tropical cyclone. On 22 February, Eline made landfall about 80 km (50 mi) south of Beira, Mozambique, near peak intensity. Eline quickly weakened over land as it moved across Southern Africa, finally dissipating over eastern Namibia on 29 February.

While moving across much of the Indian Ocean, Eline brought high waves, gusty winds, and rainfall to several islands. When Eline struck Madagascar, the country was in the midst of a cholera epidemic that killed over 1,000 people. Eline directly killed at least 64 people in the country. Tropical Storm Gloria struck Madagascar 13 days later, compounding the damage and making it difficult to discern the individual effects. Damage from Eline was estimated at $9 million (USD), and collectively the two storms killed 205 people and left another 10,000 homeless. In the region around Vatomandry where Eline made landfall, 65% of houses were damaged, 90% of crops were lost, and 75% of health facilities were wrecked.

Before Eline's final landfall, Mozambique's worst floods since 1951 had killed about 150 people. The additional rainfall and flooding from Eline created the country's worst natural disaster in a century, and disrupted ongoing relief efforts. The combined effects destroyed over 250,000 ha (620,000 acres) of crop fields and killed 40,000 cattle. The Limpopo River reached 15 km (9.3 mi) wide and 11 m (36 ft) above normal in some areas, which isolated the town of Xai-Xai. A dam broke along the river, flooding the town of Chokwe in the middle of the night and trapping several unprepared residents; this accounted for nearly half of the death toll. About 55 people drowned in Sofala Province after rescue helicopters arrived too late to save them. Around 20,000 people in the capital city of Maputo lost their homes. In addition to the floods, strong winds blew away many roofs and some entire houses made of mud. The combined effects of the preceding floods and Eline left about 329,000 people displaced or homeless, killed around 700 people, and caused an estimated $500 million (USD) in damage. The flooding disrupted much of the economic progress Mozambique had made in the 1990s since the end of its civil war.

Elsewhere in Southern Africa, Eline brought strong winds and heavy rainfall when it crossed into eastern Zimbabwe. Rivers overflowed their banks in the country, damaging crops and houses while leaving 15,000 people homeless. The storm killed 12 people in the country. Flooding from the storm extended southward into Swaziland and South Africa. In the latter country, Eline dropped 503 mm (19.8 in) of rainfall in Levubu over three days, causing the Limpopo River to reach its highest level in 15 years. Officials opened dams along the river to prevent structural damage, which caused higher levels along the river to the east. At least 21 people died in the country, and about 80,000 people were left homeless. Damage in Limpopo Province alone was estimated at $300 million (USD). To the north, Eline dropped about 90 mm (3.5 in) of rainfall in southern Malawi, while gusty winds caused a power outage in Blantyre. Farther west, rainfall rates of 50–100 mm (2.0–3.9 in) were reported in Botswana.

The origins of Cyclone Leon–Eline were from a surge of energy within the monsoon trough that crossed the equator from the northwest, which spawned a low pressure area on 1 February in the eastern Indian Ocean, about 250 km (160 mi) south of the Indonesian island of Bali. Associated convection, or thunderstorms, was initially sparse due to wind shear in the region. Over the next few days, the low tracked west-southwestward without much development, moving around a large ridge over northwestern Australia. An anticyclone over the system provided outflow, allowing convection to increase despite the wind shear. At 22:00 UTC on 3 February, Australia's Bureau of Meteorology (BoM) upgraded the tropical low to a Category 1 tropical cyclone on the Australian tropical cyclone scale, estimating 10‑minute sustained winds of 65 km/h (40 mph). At 04:00 UTC the next day, the BoM named the storm Tropical Cyclone Leon. On the same day at 03:00 UTC, the Joint Typhoon Warning Center (JTWC) began issuing advisories on the storm as Tropical Cyclone 11S. Around that time, Leon was located about 215 km (134 mi) south-southeast of Christmas Island, moving west-southwestward. With decreasing wind shear, the convection organized into rainbands, signaling that the storm was strengthening.

Early on 5 February, the BoM upgraded Leon to a Category 3 severe tropical cyclone on the Australian scale, estimating 10‑minute winds of 120 km/h (75 mph). At 22:00 UTC that day, the agency estimated an initial peak of 140 km/h (87 mph). On 6 February, the cyclone developed an eye in the center of the convection that was only visible on Special sensor microwave/imager, not on satellite imagery. On the same day, the JTWC upgraded Leon to the equivalent of a minimal hurricane, estimating 1‑minute winds of 140 km/h (87 mph). A trough passing to the south increased wind shear, causing the storm to weaken. Around that time, Leon passed about 510 km (320 mi) south of the Cocos Islands, while turning more to the west after the ridge strengthened to the south. By 8 February, the circulation was exposed from the rapidly dwindling thunderstorms. At 18:00 UTC that day, Leon crossed 90° E into the south-west Indian Ocean, and as result was renamed Eline by the Mauritius Meteorological Service. By that time, Météo-France (MFR) estimated 10‑minute winds of 65 km/h (40 mph).

Over the subsequent few days, wind shear caused the convection to wax and wane over Eline's center, limiting the thunderstorms to the southern periphery. The track shifted more to the west-northwest. On 11 February, Eline had weakened into a minimal tropical storm according to the MFR, about 1,110 km (690 mi) south of Diego Garcia, and the JTWC operationally downgraded it to a tropical depression. Later that day, however, a decrease in shear allowed thunderstorms to refire. On 13 February, a weakness in the ridge caused the storm to turn back to the west-southwest. Moving back beneath an anticyclone, conditions became more favorable for strengthening, allowing outflow and a central dense overcast to form, with the beginnings of an eye feature. Eline quickly intensified into a severe tropical storm later the same day. At 00:00 UTC the next day, the JTWC upgraded Eline to the equivalent of a minimal hurricane with 1‑minute winds of 120 km/h (75 mph). The MFR held off upgrading the storm, due to a passing trough increasing wind shear again. On 14 February, Eline passed about 85 km (53 mi) south of St. Brandon, and shortly thereafter resumed its strengthening after the shear dropped. Later that day, the storm bypassed Mauritius about 180 km (110 mi) to the northwest, with the storm's small structure sparing the island from the strongest winds. Early on 16 February, Eline attained tropical cyclone status, with 10‑minute winds of 120 km/h (75 mph), while passing about 160 km (99 mi) northwest of Réunion. This was nine days after it had weakened to tropical storm status the first time.

Upon becoming a tropical cyclone, Eline was still encountering wind shear and dry air. Despite these factors, the eye became better defined and the storm intensified as upper-level conditions improved. The cyclone turned more to the west toward Madagascar, despite a weakness in the ridge to the south. While approaching the country, Eline quickly intensified, reaching 10‑minute winds of 165 km/h (103 mph) by 18:00 UTC on 17 February. Around that time, the cyclone made landfall on eastern Madagascar near Mahanoro. Eline rapidly weakened over land while moving to the west-southwest, and the JTWC downgraded the storm to tropical depression status within 18 hours of moving ashore.