Flood in the Sahara: how is it possible in Africa?

When we think of the Sahara, images of endless dunes and hot sand come to mind. However, North Africa is currently facing an unprecedented phenomenon – a flood in the desert. Morocco and Algeria have experienced intense rainfall, resulting in 20 fatalities so far. A flood in a region where rain is rare not only surprises but also raises questions about the future of climate change and its impact on areas so unaccustomed to excess water.

The Sahara is one of the driest regions in the world, receiving just a few millimeters of rain annually. However, it turns out that weather anomalies can lead to flooding even in the desert. Last month, a tropical cyclone swept through the desert, affecting the northwestern part of the Sahara, flooding Morocco, Algeria, Tunisia, and Libya. Although most of the rainfall occurred in sparsely populated areas, the Moroccan authorities reported significant damage – roads were damaged, and power and water supplies were disrupted in regions with poorly developed infrastructure.

Cyclone – the cause of the Sahara flood

The culprit behind the flood in the Sahara is a cyclone that formed over the Atlantic Ocean and stretched far to the south, pulling moisture from equatorial Africa into northern Sahara. Preliminary satellite data indicate an accumulation of several dozen to over 200 mm of rainfall in the affected areas. This is a lot for this location – almost as much as the region receives in an entire year. These estimates are based on data from NASA’s Integrated Multi-Satellite Retrievals for GPM (IMERG) system, which allows for systematic monitoring of rainfall over vast areas of the Sahara. Satellite images also showed that the dry lakes of the Sahara filled with water.

According to IMERG data from the past two decades, among hundreds of atmospheric phenomena that have affected the Sahara, only six led to the filling of a lake. Out of 38,000 heavy rainfall events recorded in this area, around 30% occurred during the summer. It is worth noting that only a small number of these events were associated with tropical cyclones, highlighting the rarity of such phenomena in this region.

Will the flood in the Sahara alleviate the drought?

Rainfall in the southern Sahara is primarily associated with the arrival of monsoon lows in the summer, tropical waves from the east, and convection resulting from orographic lifting and surface heating near the Sahara heat low. Occasionally, rainfall can also be associated with extratropical cyclones, which bring unusually heavy rains to the region.

While these events are rare, they can temporarily replenish underground aquifers, which are vital for supplying water to communities living in the desert. The intense rainfall observed in September 2024 contributed to a record filling of water reservoirs in the region.

Flooding in the Sahara seemed impossible. Although heavy rains may temporarily ease water access issues, the long-term consequences of such anomalies may prove difficult for local communities. African countries, often struggling with a lack of infrastructure and resources, now face new challenges.

Climate change affects every corner of the Earth

Recent events have clearly shown that no place on Earth is free from the consequences of climate change. Where water was once scarce, it has become even more valuable, but equally dramatic effects are being seen in regions that until now have never experienced water shortages. The forces of nature are breaking previous patterns, bringing unpredictable consequences in both dry desert landscapes and areas that have historically enjoyed stable water resources. This is a reminder that global climate change operates beyond geographical boundaries, affecting people, nature, and ecosystems that once seemed beyond its reach.