Rainfall subsides in late November, reducing flood risk and enabling recessional cultivation in southern Somalia

The purpose of this document is to provide updated information on the progress of the October to December deyr season to facilitate contingency and response planning. This Somalia Seasonal Monitor is valid through December 20, 2023, and is produced in collaboration with U.S. Geological Survey (USGS), the Food Security and Nutrition Analysis Unit (FSNAU) Somalia, the Somali Water and Land Information System (SWALIM), a number of other agencies, and several Somali non-governmental organizations (NGOs).

Driven by El Niño and positive Indian Ocean Dipole climate conditions, Somalia continued to experience moderate to heavy rainfall during the November 11-20 period, near the middle of the October to December deyr season. Following this, most areas of Somalia as well as the Ethiopian highlands that feed the Juba and Shabelle Rivers experienced suppressed rainfall between November 21 and December 10, reducing the risk of further floods. Ground reports and remote-sensing data confirm above-average rainfall and flooding continued across the southern and central regions during the November 11-20 period, followed by suppressed rainfall from late November to early December. Preliminary CHIRPS remote-sensing data for the November 11 to December 10 period indicate that most southern regions received 100-300 millimeters of rainfall while the rest of the country received 10-50 mm of rainfall, although large parts of the northern Sool, Sanaag, Bari, and Nugaal regions received less than 10 mm of rainfall (Figure 1). Compared to the long-term average (1981-2020), these rainfall totals were around 50-200 millimeters above average in southern areas and around 10-50 mm above average in central areas, though close to average in northern areas (Figure 2). Ground information also indicates that the earlier widespread flooding is easing in many Juba and Shabelle riverine areas. FAO SWALIM river station gauge data as of December 15 show a considerable decline in water levels of the the Juba and Shabelle Rivers. In almost all monitoring stations, current river water levels are significantly below the flood risk levels. However, river water levels remain high and at bankfull levels in Buloburte of Hiraan. The forecast of dry conditions in Somalia and the Ethiopian highlands in the coming days and weeks is expected to facilitate further declines in water levels of the Juba and Shabelle Rivers. 

In the northwest, following average to above-average rainfall received in late October and early November, most pastoral and agropastoral livelihoods of Woqooyi Galbeed, Togdheer, Sanaag, and Sool regions received average rainfall during the November 11-20 period. Following this, little to no rainfall was reported in these areas between November 20 and December 10, as is typical at this time of year. The deyr rainfall in October and November markedly improved rangeland conditions and pasture and water access. This has in turn improved livestock body conditions, conceptions, and reproductivity, supporting further recovery from the negative impacts of the prolonged drought.

In the northeast, similar to the northwest, rainfall between early and mid-November was close to the average in Bari, Nugaal, and northern Mudug regions, with most rainfall received in coastal and adjacent pastoral areas of Bari and Nugaal and in most livelihoods of northern Mudug. During this time, localized flooding from heavy rainfall in the region as well as in the Golis mountains of Bari along the Gulf of Aden coast caused damage to feeder roads and housing in some villages, but also replenished pasture and seasonal rivers in the valleys. However, suppressed rainfall was observed across all livelihood zones between November 20 and December 10, which is typical at this time of year. Overall, rainfall in October and November has considerably improved rangeland conditions and livestock reproduction. 

In central Somalia, widespread moderate to heavy rainfall fell across all livelihood zones of Galgaduud and southern Mudug regions during the November 1-20 period. Between November 20 and December 10, little to no rainfall was reported, with the exception of localized heavy rainfall reported during November 21-30 within the Coastal Deeh Pastoral livelihood zone and some Cowpea Belt Agropastoral areas of Ceeldheer district. This heavy rainfall resulted in livestock mortality due to drowning in parts of Ceeldheer as well as human displacement from Ceeldheer town. On the other hand, rainfall throughout October and November has substantially improved rangelands and livestock conditions. 

In the southern regions, significant rainfall, ranging from moderate to heavy intensity between late October and early November, continued into November 11-20, further inundating the southern livelihoods across. The torrential rains exacerbated the impacts of prior flooding in affected areas, causing further crop damage, hindering market activities, and driving additional population displacement from riverine and lowland agropastoral areas. During the November 11-20 period, rainfall gauge data recorded precipitation levels of 212 mm in Afgoye (Lower Shabelle), 198 mm in Sakow (Middle Juba), 194 mm in Xudur (Bakool), 163 mm in Baidoa (Bay), 48 mm in Beledweyne (Hiiraan), and 10 mm in Jamaame (Lower Juba). However, little to no rainfall was reported between November 21 and December 10, providing relief from flooding in early December and allowing for the beginning of recessional off-season cultivation activities in most riverine and localized flood-affected agropastoral areas. Due to the suppressed rainfall since late November, river water levels have been gradually declining across most riverine areas of the south. 

The eVIIRS Normalized Difference Vegetation Index (NDVI) for December 1-10 shows widespread positive vegetation anomalies across the country (Figure 3), attributed to the average to above-average deyr rainfall in October and November. However, negative anomalies persist in some localized riverine and agropastoral areas of the Middle Shabelle and Bay regions, likely due to flood cover (Figure 3). According to the NOAA Climate Prediction Center's 7-day forecast through December 20, dry conditions are likely in the Ethiopian highlands and across all areas of Somalia, except for limited localized coastal areas of the Shabelle and Juba regions, where light rainfall is forecast (Figure 4). The suppressed rainfall in December will likely further ease the flooding in areas along the Juba and Shabelle rivers. 

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