Deep Diving into the “Post 1.5 °C Climate” Heatwave Events in Ouagadougou During Spring 2024

The West African Sahel suffered an unprecedented hot season during spring 2024 especially marked by noticeable heatwave episodes in the urban context of Burkina Faso’s capital, Ouagadougou, where significant impacts were reported. These heat events are analyzed to link hazards with impacts and improve early warning systems in the under-recognized Sahel context. Using observational data from the Burkina Faso National Meteorological Agency and the European reanalysis, ERA5, anomalies of both daily maximum (Tmax) and minimum (Tmin) temperatures were analyzed. The results show that, during the first half of 2024, monthly Tmax and Tmin anomalies were highly positive compared to the reference period 1991–2020. A total of four daytime and one nighttime heatwave events were detected. The longest daytime heatwave lasted six days with observed Tmax reaching 44.5 °C. The unique nighttime heatwave was at least twice as long as the longest daytime heatwave, persisting 13 days between late April and early May. In addition, the heat was not evenly distributed spatially as some districts were significantly hotter than the rest of the city, suggesting possible urban/local effects. These results underscore the occurrence of exceptional heat in 2024 and the need for efforts towards heatwave risk mapping and management in African cities.