What Southern Africa's strengthening cyclones mean for local re/insurance

The nature of cyclones in the South Indian Ocean is changing. Storms are becoming more intense and are moving further south within the region, potentially impacting areas outside of the historical Indian Ocean cyclone belt. The result is that countries in future cyclones' southerly paths may not be adequately prepared for these natural disasters and insurers, not correctly positioned to cover the losses.

There are seven tropical cyclones basins around the world, each located within the oceans where these storms typically develop. There is only one cyclone basin associated with Africa - the South Indian Ocean basin, responsible for the cyclones that impact Mauritius, Madagascar, Mozambique, Tanzania and South Africa.

CAT 5 storms to become the norm?

Tropical cyclones require a sea surface temperature of around 26.5°C to form. In recent years, the surface temperature of the ocean has begun to climb, with temperatures of around 30°C being recorded over longer periods of time. This is contributing to the formation of higher intensity storms than previously seen.

Since 1994, the frequency of category 5 cyclones has increased in the South Indian Ocean, with 12 such storms having taken place between 1994 and 2016. By comparison, there were no CAT 5 cyclones recorded in this basin in the period between 1970 and 1993.

However, even storms that do not sustain their category 5 status and make landfall, have become increasingly destructive. In Mozambique, cyclones Idai (2019) and Freddy (2023) are rated as the two deadliest cyclones recorded in Mozambique in recent years. Idai was a major category 4 storm and Freddy was a category 5 storm that weakened to a category 3 event when it made landfall.

Mainland Africa at risk

In her South African Journal of Science paper, Recent emergence of CAT5 tropical cyclones in the South Indian Ocean, author Jennifer Fitchett outlines what she calls the 'poleward migration' of Southern Africa's cyclones.

Fitchett, a professor at the School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, studied tropical cyclones in the South Indian Ocean basin using a data set endorsed by the World Meteorological Organisation dating back to 1842.

She noted that the dynamics for the South Indian Ocean were poorly understood. The early results of her study, for instance, indicated "an increased frequency and poleward migration of these CAT5 storms, concurrent with a poleward migration in the position of the 26.5 °C, 28 °C and 29 °C sea surface temperature isotherms in the South Indian Ocean."

Fitchett said that the poleward trajectory of these storms, combined with global studies indicating a poleward trajectory in the lifetime maximum intensity of tropical storms posed a heightened threat for South Africa.

Historically, South Africa has been protected from cyclones by Madagascar. But this new trajectory could see cyclones largely missing that country and making landfall on South Africa's east coast instead.

In addition to warming ocean surface temperatures, two other weather phenomena - the El Niño Southern Oscillation and the Indian Ocean Dipole - also play contributing roles in the development and trajectory of cyclones. El Niño events, for instance, increase the likelihood of cyclones changing direction and possibly moving further south.

Fitchett believes this recent emergence of tropical cyclones attaining category five intensity in the South Indian Ocean is of significance for the forecasting of tropical cyclone landfall and the anticipation of storm damage for the region's vulnerable, developing economies.

Old cyclone pathways re-emerging

Interestingly, Cyclone Kenneth in 2019, also a category 4 storm, travelled further north than any other recently recorded cyclone, hitting not only northern Mozambique but Tanzania too. It was reportedly only the third ever cyclone to make landfall in Tanzania. The other two being in 1952 and 1872, which has raised the question, 'are forgotten cyclone paths beginning to emerge again?'.

At the time, Kenneth was the strongest tropical cyclone to make landfall in Mozambique since modern records began. This supports predictions of South Indian Ocean cyclones increasing in strength, and unexpected pathways, in the future.

A recent storm that demonstrated an unusual southbound trajectory was Australia's Cyclone Alfred in March 2025. What made Alfred unique was that it made landfall near Brisbane, the country's third-most populous city. It is extremely rare for tropical cyclones to hit Australia's east coast as far south as Alfred did - the last one to do so was Cyclone Zoe in 1974.

More than 95 000 insurance claims were received following the cyclone, with the majority of claims relating to food spoilage, wind damage and water ingress.

Changing cyclones' impact on reinsurance

While the Insurance Council of Australia (ICA) says it is too early to say what the impact of this event will be on the re/insurance industry, it noted that "in response to extreme weather costs", reinsurers in 2024 already had pushed reinsurance costs to 20-year highs.

The Financial Stability Institute, a body of the Swiss Bank of International Settlements, says increasing insured losses, partly due to climate change, are putting pressure on the availability and affordability of reinsurance coverage.

It notes that increasing climate-related risks and risk uncertainties are driving up reinsurance premiums and/or reducing coverage. As a result, some reinsurers may no longer be able to sustainably provide coverage, impacting insurance availability and affordability.

Increased natural catastrophe frequency and severity result in higher claims and therefore strains on capital reserves, adding an extra burden on reinsurance companies.

Accurate natcat modelling now critical for African clients

In the face of both this increasing risk and pressure on re/insurers, accurate risk management and catastrophe modelling have never been more important. Reinsurance Solutions leverages industry-leading catastrophe modelling to deliver clarity to clients operating in Southern Africa.

With increasing cyclone frequency and severity, probabilistic models enable insurers to understand, price and transfer risk more effectively, while detailed outputs help clients correctly structure reinsurance programmes, optimising capital and resilience.

Reinsurance Solutions uses a probabilistic model that estimates damage due to both tropical cyclones and tropical depressions originating in the South Indian Ocean.

It draws on extensive data captured in the South Indian Ocean basin, and rigorous industry data, including the Joint Typhoon Warning Centre records and the Monte Carlo simulations, ensuring a high degree of reliability and convergence in loss estimation.

Using a robust database of 3,916 stochastic storms that simulate a vast range of possible cyclone events affecting Reunion and surrounding islands, the model incorporates meteorological features (wind speed, storm tracks, landfall location, event intensity) as well as the annual frequency of occurrence.

It also includes land use and property characteristics to accurately estimate potential damages. The vulnerability module refines results by capturing structure type, occupancy, year built, and number of stories, allowing for granular, location-specific loss estimates.

Modelling benefits for clients

Clients operating along the east coast of Southern Africa and on the Indian Ocean Islands have access to extremely detailed information not only of current-type events, but future, more severe events as well.

This is essential given the forecast for increasingly unpredictable tropical storms in the future impacting areas not typically in cyclone paths - and the risk for greater flooding into previously untouched surrounding regions, as stronger storms raise the geographical spread of flood waters.

Within Reinsurance Solutions' cyclone model, catastrophe purchase levels are conservatively set, often in excess of a 1-in-1,000-year return period, providing robust protection against rare but severe events.

Accurate cyclone modelling is one of Reinsurance Solutions' standout capabilities, separating it from other reinsurance brokers in Africa. Its knowledge and firsthand experience of operating within a cyclone belt itself for more than 28 years, combined with its unparallelled modelling capabilities, truly sets it apart.

The brokerage is committed to continuous innovation, working with the latest science and modelling techniques to ensure clients are always prepared for what's next, even when cyclone patterns are unpredictable.