ABSTRACT Réunion is characterised by a rugged topography formed by two volcanoes. The small size of the island makes tropical cyclone (TC) landfalls relatively uncommon, despite the geographical location within an exceptionally active ocean basin. As much of the research on tropical cyclones focusses on landfall, Réunion has therefore been comparatively overlooked. Due to the size of the storms, the seasonal movement of tropical cyclones within a 500 km radius of Réunion is likely to have an impact on local weather. The extent of this influence of non‐landfalling tropical cyclones on the transient weather of the island remains uncertain. To investigate this issue, a record was compiled of tropical cyclones that made passage within a 500 km radius of Réunion from 1991 to 2023 using the IBTrACS database. The conditions of each cyclone were then compared to meteorological data, provided by Météo France, for 11 stations across the island from 1991 to 2023. The results indicate that even the lowest intensity tropical cyclones making passage 500 km away from the island can result in significant deviations from long‐term weather in Réunion. Storm intensity, direction, duration and seasonality all play an equally important role in the effect size of the deviations in meteorological conditions. The most marked changes, in terms of effect size, to long‐term weather were induced by storms that made passage nearest the eastern coast of the island, those during February, and those which intensified most rapidly. These findings suggest that non‐landfalling tropical cyclones are far more impactful than expected, highlighting the significance of precautionary tropical cyclone adaptations.
Marinaki et al. (Tue,) studied this question.