Poor onset and performance of October deyr rainfall observed across most of Somalia

Consistent with multi-ensemble forecast models and the IGAD’s Greater Horn Climate Outlook Forecast (GHACOF62), the onset of the October-December deyr rains has either been late or performed poorly across most of Somalia. During the October 1-20 period, ground information indicates most of the country remained dry, apart from some localized areas in southern, central, and northwestern Somalia, which received light to moderate rainfall. Preliminary CHIRPS remote-sensing data suggest somewhat more widespread light rain, with most of southern and northern Somalia receiving less than 10 millimeters (mm) of rain and Nugaal, Mudug, Galgadudd, Hiraan, Bay, and Bakool regions receiving 10-50 mm of rain (Figure 1). Compared to the long-term average (1981-2020), remote-sensing data suggest cumulative rainfall in October 1-20 was largely below average in the south and near-average across the rest of the country; however, this is not consistent with the dry conditions captured by ground information (Figure 2). According to FAO SWALIM river station gauge data on October 20, river water levels at key monitoring points along the Shabelle and Juba rivers range from below average to above average, with favorable levels linked to rainfall in the upper river catchments in the Ethiopian highlands.

In the northwest, the deyr rains, which normally begin in early October, had yet to fully begin in most pastoral and agropastoral livelihood zones as of October 20. Localized light to moderate rainfall occurred in most pastoral areas of Togdheer and Sool regions, but pastoral areas in Sanaag Region received little to no rain. However, the July-September karan rains extended into October in pastoral and agropastoral areas of Awdal and Woqooyi Galbeed regions. Furthermore, Guban Pastoral areas of Awdal, which does not typically receive either gu or karan rainfall, saw localized flooding related to rain in the mountainous, neighboring West Golis Pastoral areas. Overall, though, vegetation and water conditions remain atypically dry to semi-dry across most pastoral areas of Togdheer, Sool, and Sanaag, and any positive impacts from the localized rain will be quickly depleted by a large influx of livestock that have migrated within or from outside these regions in search of pasture and water.

In the northeast, the deyr rains had yet to start in most pastoral livelihood zones of Bari and northern Mudug as of October 20. In most pastoral areas of Bari and Mudug, pasture, browse, and water resources are scarce, and commercial water trucking is the primary source of water for most pastoral households despite significantly above-average prices. However, reports of localized light to moderate rainfall were emerging in Northern Inland Pastoral areas of Qardho, Bandarbeyla, Iskushuban, and Bossaso districts and pastoral areas of northern Mudug and southern Nugaal toward the end of the October 1-20 period.

In central regions, the onset and performance of the deyr rains have been mixed so far. During the October 1-20 period, reports indicated localized light to moderate rainfall occurred in most livelihood zones of Galgaduud and southern Mudug. According to field reports, moderate rainfall with fair distribution tended to be concentrated in Addun Pastoral, Hawd Pastoral, and Cowpea Agropastoral livelihood zones. In contrast, little to no rainfall was reported in Coastal Deeh Pastoral areas. Although these rains have temporarily alleviated water shortages, the protracted and extreme nature of the drought means the water requirements of rangeland resources are currently very high. As a result, most of these areas continue to face considerable pressure on meager resources.   

In the south, both ground information and satellite imagery show that the deyr rains, which normally begin in mid-October, have not yet effectively begun in most regions. During the October 11-20 period, field reports indicated that agropastoral areas of Lower Shabelle, Bay, and Bakool regions and localized areas of Southern Inland Pastoral zone in Lower Shabelle received only light to moderate rain, while the Juba and Gedo regions received little to no rainfall at all. Rain gauge stations captured moderate rainfall amounts in the following areas: 100 mm in Xudur (Bakool), 42 mm in Elbarde (Bakool), 43 mm in Baidoa (Bay), and 40 mm in Qansahdhere (Bay). However, no rainfall was recorded at rain gauge stations in Dinsor (Bay), Sakow (Middle Juba), Jamame (Lower Juba), Janaale and Afgoye of Lower Shabelle and Beledweyne (Hiraan). Most of the SWALIM’s river gauge stations along the Shabelle River indicated above-normal river water levels, but well below flood risk; most stations along the Juba River showed below-normal levels except in Dolow. Ground information shows the current river water levels are adequate to support riverine irrigation activities.    

According to the satellite-derived eVIIRs Normalized Difference Vegetation Index (NDVI) for the period of October 11-20, vegetation conditions in most areas of the country are largely below typical levels (Figure 3). This comes in the aftermath of four consecutive seasons of poor seasonal rainfall. The seven-day weather forecast from the NOAA Climate Prediction Center through October 31 indicates a likelihood of widespread dry conditions for most areas (Figure 4). In contrast, localized pastoral areas of Sool, Nugaal, Mudug, and Galaduud and parts of Hiraan, Bay Bakool, and Gedo are likely to receive rainfall during this period. Since rainfall in the Ethiopian Highlands is not forecast to be heavy, it is highly unlikely that the levels of the Shabelle and Juba rivers pose a significant flood risk through the end of the month.

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