Flooding in southern and central Somalia due to heavy deyr rainfall and high river levels

Reports from the field, corroborated by remote-sensing data, indicate above-average rainfall associated with a strong El Niño and positive Indian Ocean Dipole (IOD), particularly in southern Somalia, from November 1-10. According to preliminary CHIRPS remote-sensing data for November 1-10, most southern and central regions received 50-150 millimeters (mm) of rainfall, triggering flash and river flooding in the riverine and some agropastoral areas (Gedo, Juba, Shabelle, Bay, Bakool, and Hiiran regions). Meanwhile, the rest of the country generally received 5-25 mm of rainfall, with some localized areas in the northwest and northeast (parts of Awdal, Sanaag, Bari, and Nugaal) receiving less than 5 mm. Cumulative rainfall from November 1-10 was 10-100 mm above the long-term average (1981-2020) in the south-central areas and average in most northern areas. According to FAO SWALIM river station gauge data, as of November 15, river water levels have surpassed high flood risk and reached bank full across all monitoring stations along the Juba and Shabelle rivers except for two stations along the Shabelle, including Buloburte in Hiiraan region where water levels are between moderate and high flood risk and Jowhar in Middle Shabelle region where the levels are below moderate flood risk. Given the continuous heavy rainfall in Somalia and the Ethiopian highlands, there is a potential for more widespread flooding in the riverine areas in the coming days. 

In the northwest, mixed deyr rainfall continued from November 1 to 10. Localized areas of Awdal region and East Golis Pastoral livelihood zone in Sanaag region experienced limited precipitation. Conversely, most livelihood zones in Woqooyi Galbeed and Togdheer regions and localized portions of Northern Inland Pastoral and West Golis Pastoral livelihood zones in Sanaag and Sool regions experienced moderate to heavy rainfall. Rainfall generally ranged from average to slightly above average relative to the long-term mean. Overall, the varied rainfall patterns in these areas improved rangeland conditions, enabling migration opportunities for pastoralists and livestock, especially from rain-deficit areas of Sanaag regions.

In the northeast, mixed rainfall performance characterized by localized light to moderate rainfall in Bari region and moderate to heavy rainfall in Nugaal and southern Mudug regions continued from November 1 to 10. In some parts of Northern Inland and Hawd pastoral livelihood zones in western Bari and Nugaal regions, less than 5 mm of rain was observed during the period. Meanwhile, moderate to heavy rainfall was observed in the eastern and coastal portions of the northeast, including Coastal Deeh, Northern Inland, and Addun Pastoral livelihood zones in northern Mudug and parts of eastern Bari and Nugaal regions. Overall, rangeland conditions have significantly improved with the deyr rains in Nugaal and northern Mudug regions, while rangeland conditions in many areas of Bari region remain below average.

In central regions, field reports confirm that moderate to heavy deyr rainfall continued through November 10 across the regions. In some areas, extremely heavy rainfall caused flash flooding that destroyed rural houses, displaced households, and resulted in both human and livestock fatalities, especially in Galkayo town and localized parts of Coastal Deeh Pastoral and Cowpea Agropastoral livelihood zones in Xarardheere district in southern Mudug region. While the heavy rainfall has caused considerable damage, pasture conditions and access to water across the central regions have improved, breaking the five-season drought from 2020-2023.   

In the southern regions, torrential rainfall continued through November 10, triggering severe flash and river floods in most regions, damaging croplands, disrupting deyr seasonal cultivation, hindering market activities, and resulting in fatalities and displacement in several riverine and agropastoral areas, and internally displaced persons (IDP) settlements. During this period, rain gauge data recorded precipitation levels of 117.6 mm in Beledweyne district (Hiiraan), 275.5 mm in Baidoa district (Bay), 223.5 mm in Xudur district (Bakool), 56 mm in Afgoye district (Lower Shabelle), 85 mm in Sakow district (Middle Juba), and 40.5 mm in Jamaame district (Lower Juba). The local heavy rains were exacerbated by torrential rains in the Ethiopian highlands, contributing to the flooding of the Juba and Shabelle riverine areas and localized agropastoral areas in Bay, Bakool, Gedo, Shabelle, and Juba regions in the south. 

The eVIIRS Normalized Difference Vegetation Index (NDVI) for November 1-10 shows positive vegetation anomalies nationwide, attributed to improved and above-average deyr rainfall in October and November. However, negative anomalies are observed in some southern riverine, coastal, and agropastoral areas, reflecting the ongoing flood damage from El Niño-enhanced rainfall (Figure 3). NOAA Climate Predication Center's forecast for November 14-20 predicts moderate to heavy rainfall in most southern and northern regions, with minimal rainfall expected in Bari and the eastern parts of Sool and Sanaag in the north. The forecasted heavy rain in the Ethiopian highlands over the same period will likely exacerbate the ongoing flooding in the southern regions, increasing the risk of flooding in riverine areas.

For more rain gauge data, please contact So-Hydro@fao.org or visit www.faoswalim.org.