Africa does experience powerful rotating storms, but the term used depends on the body of water where they occur. The word “hurricane” is specifically reserved for storms that form in the North Atlantic Ocean and the Northeast Pacific Ocean. When these intense weather systems affect the African continent and its neighboring islands, they are referred to by a different name specific to the region. The continent is overwhelmingly impacted by storms on its eastern side, while the western coast remains largely protected due to distinct meteorological and geographical factors.
Defining the Storms Near Africa
The global meteorological community uses different names for the same type of rotating tropical weather system based on the ocean basin of origin. The World Meteorological Organization (WMO) coordinates this naming system to ensure clear communication and tracking of storms. In the North Atlantic, the storms are called hurricanes, while those in the Northwest Pacific are known as typhoons.
The storms that impact Africa are primarily generated in the South-West Indian Ocean basin, where they are officially designated as tropical cyclones. This basin is monitored by the Regional Specialized Meteorological Center (RSMC) in La Réunion, operated by Météo-France. This regional center is responsible for issuing official forecasts and assigning names to systems that reach tropical storm strength within the area, which extends from the African coast eastward to 90° E and south of the equator.
A system is classified as a tropical cyclone only when its ten-minute sustained wind speeds reach at least 74 miles per hour (120 kilometers per hour), which is equivalent to a Category 1 hurricane on the Saffir-Simpson scale. This consistent terminology helps to reduce confusion when communicating warnings to the affected island nations and coastal regions.
Primary Impact Zones and Seasonality
The most frequent and devastating impacts of tropical cyclones near Africa occur along the continent’s eastern coast and the island nations of the South-West Indian Ocean. Madagascar is the most vulnerable territory, experiencing direct hits from several systems each season. The storms often make landfall on the eastern coast of Madagascar, bringing immense rainfall and destructive winds before weakening as they cross the mountainous interior.
After passing over Madagascar or forming directly in the Mozambique Channel, many cyclones threaten the mainland African coast, particularly Mozambique and Tanzania. These landfalls often result in widespread flooding due to storm surge and torrential rain, especially in low-lying coastal areas. Further south, the islands of Réunion, Mauritius, and the Comoros are also directly exposed to these powerful systems.
The official tropical cyclone season for the South-West Indian Ocean basin runs for six months, beginning on November 15 and concluding on April 30. While storms can occasionally form outside of these dates, peak activity occurs during the warmest summer months of the Southern Hemisphere, from December through March. During this peak period, the ocean surface temperatures are highest, providing the necessary energy for tropical systems to form and intensify.
The Meteorological Factors Governing Storm Tracks
The dramatic difference in storm activity between Africa’s eastern and western coasts is the result of several atmospheric and oceanic conditions. The South Atlantic Ocean, which borders the West African coast, generally presents a hostile environment for tropical cyclone development.
A primary inhibiting factor is the relatively cool Sea Surface Temperatures (SSTs) along the coast, which are often below the 80°F (26.5°C) threshold required to sustain a tropical system. This cooler water is largely due to the Benguela Current, which brings cold water northward from the deep South Atlantic, effectively suppressing the formation of the warm, humid air masses needed to fuel a cyclone.
Furthermore, the region is frequently subject to high levels of vertical wind shear, which is a rapid change in wind speed or direction with altitude. This strong shear tears apart the developing vertical structure of a storm before it can organize into a rotating cyclone.
In the North Atlantic, the development of potential storms is often hindered by the Saharan Air Layer (SAL), a mass of hot, dry, and dusty air that moves west off the Sahara Desert. This dry air significantly reduces the moisture content in the atmosphere, preventing the formation of the deep convective thunderstorms that are the building blocks of a tropical cyclone. The combination of dry air, strong shear, and cooler waters creates a natural barrier that protects the West African coastline from direct impacts.
Another significant factor is the Coriolis effect, the force created by the Earth’s rotation that causes moving air to deflect and rotate. This effect is weakest near the equator. Since a significant portion of the West African coast lies very close to the equator, the Coriolis force is insufficient to initiate the tight, sustained spin required for a low-pressure area to consolidate into a powerful tropical cyclone. Almost all tropical cyclones form at least 300 miles (500 kilometers) away from the equator, pushing the formation zone away from the west coast and toward the East African basin.