Analysis of the 16-20 February 2025 Damaging Heavy Rainfall in Botswana

Heavy rainfall that occurred from 16-20 February 2025 over most of Botswana caused, for example, flash flooding, fatalities, and widespread displacement, with the most severe impacts in the Gaborone-Mochudi region in the southeastern parts of the country. The drivers of this event are poorly understood; hence, this study analyses the rainfall characteristics using CHIRPS and station data. It also analyses related atmospheric circulation anomalies using ERA5 reanalysis. Results show that the event produced rainfall anomalies that exceeded two standard deviations, making it one of the three most intense events in the 1981-2025 period. ENSO had a limited role in driving the event because it showed weak correlations with rainfall and La Niña conditions were weak. The event was mainly driven by a weakened Botswana High, an intensified Angola Low, enhanced mid-level uplift, and increased moisture transport from adjacent tropical South East Atlantic and South West Indian Oceans. These findings show that it is not only ENSO forcing that triggers extreme rainfall events in the region, but complex interactions between regional circulation systems and oceanic moisture sources can also play a major role. There is therefore a need to design or upgrade infrastructure for higher rainfall extremes. There is also a need for early warning systems to incorporate regional circulation systems to improve forecasting skill.