Rainfall in April 2018 was well above average (higher by 50% or more compared to the long-term average for April) in most parts of Somalia and adjacent areas in Ethiopia. As a result, riverine and flash floods have already caused massive population displacement, damaged housing, property, infrastructure and farm lands in riverine and low-lying areas in central and southern Somalia The overall seasonal rainfall amount and river levels and extent of flooding are likely to be worse than in 2006 but less compared to 1997; however, humanitarian impact is expected to be higher in 2018 given population increases in the affected areas. Flooding can be expected to worsen over the next 2-3 weeks as Gu season rainfall continues; however, forecasts indicate reduced rainfall activity over the next two weeks.

With the high water levels and over bank spillage in Belt Weyne, River levels at Bulo Burti are fast approaching the high risk threshold. The high water levels are expected to be transmitted to Middle and Lower Shabelle in the next couple of days and this is likely to worsen the flood situation in these areas. Communities residing in the riverine areas of Middle and Lower Shabelle, in particular, are requested to be on the alert for rising river levels and possible overspill. All necessary measures should be taken to preserve life and property in these areas.

Moderate to heavy rains will continue in the coming week in Somali and within the Ethiopian highlands whose rainfall contribute significantly to the river flow in Juba and Shabelle Rivers. Somaliland and Puntland will record the highest amounts of rainfall given the forecast. Given the current ground situation, high river levels and the rainfall forecast, riverine flooding is expected to continue and spread further especially along the Shabelle River. Flash floods are likely to be experienced in the coastal areas of Puntland (Bari and Nuugal) and central (Mudug and Galgaduud) regions.

Somalia is periodically affected by various forms of natural and manmade hazards. Floods are notably one of the most devastating natural hazards in the country, causing tremendous loss of lives and extensive damage to agriculture, vegetation, human, wild life and local economies. Juba-Shabelle River Basin is the source of the two most significant rivers (Jubba and Shabelle) in the country that provide sufficient water for crop production, livestock and for domestic use (Figure 1). It is widely believed that the alluvial plains of the two rivers to be the breadbasket of Somalia as they have considerable potential for irrigation development. However, floods are a common phenomenon in the riverine areas of the Juba and Shabelle River basin during the two main rainy seasons of Somalia Gu (April to June) and Deyr (October to December). The low-lying areas along the Juba and Shabelle Rivers are usually experienced flooding of various magnitudes. This is caused or amplified by both weather and human related factors. The natural one is due to quantity and frequency of precipitations experienced by the Ethiopian side of the Juba and Shabelle River Basin is far more exceeding than the one occurs in Somalia.

The rainfall forecast for the coming week is calling for moderate to heavy rains in most places across the country as well as the Ethiopian highlands. Following the enhanced rains observed river levels remained high along the two rivers. Belet Weyne in Hiraan region has been at bank full level for the last 14 days and is expected to remain the same for the next couple of days. Many stations along the Juba also reached their highest level in the recent history. Continued heavy rains and high river levels have led to flooding which currently exceeds a 50 year return period flood magnitude.

During the week ending on 17 April 2018, the Juba and Shabelle basins in Somalia and in the Ethiopian highlands continued to receive moderate to heavy rains. Following the heavy rains, flash floods were reported in many places within the two basins leading to displacements, inundation of croplands and destruction of property. The table below shows the total rainfall amounts recorded in selected stations within the two basins over the last one week. Map 1 shows the total Satellite Rainfall Estimates (RFE) of last week which shows moderate to heavy rains within the basins. Middle and Lower Juba regions received the highest amounts of rainfall of more than 100mm in total over the week. Map 2 shows the rainfall forecast for coming week valid until 24 April 2018 and is calling for more rains in the basins. Following the good rains river levels along the Juba and Shabelle rivers continued to rise reaching the high flood risk levels in the upper and mid sections of the two rivers. Given the rainfall forecast and the high river levels, there is a high risk of flooding in the middle and lower reaches of the Juba and Shabelle rivers with some sections having experienced overbank river flow due to weak river embankments and open river breakages. Flash floods in built up and low lying areas within the basins cannot be ruled out during the period under review

Long and temporally consistent rainfall time series are essential in climate analyses and applications. Rainfall data from station observations are inadequate over many parts of the world due to sparse or non‐existent observation networks, or limited reporting of gauge observations. As a result, satellite rainfall estimates have been used as an alternative or as a supplement to station observations. However, many satellite‐based rainfall products with long time series suffer from coarse spatial and temporal resolutions and inhomogeneities caused by variations in satellite inputs. There are some satellite rainfall products with reasonably consistent time series, but they are often limited to specific geographic areas. The Climate Hazards Group Infrared Precipitation (CHIRP) and CHIRP combined with station observations (CHIRPS) are recently produced satellite‐based rainfall products with relatively high spatial and temporal resolutions and quasi‐global coverage. In this study, CHIRP and CHIRPS were evaluated over East Africa at daily, dekadal (10‐day) and monthly time‐scales. The evaluation was done by comparing the satellite products with rain‐gauge data from about 1,200 stations. The CHIRP and CHIRPS products were also compared with two similar operational satellite rainfall products: the African Rainfall Climatology version 2 (ARC2) and the Tropical Applications of Meteorology using Satellite data (TAMSAT). The results show that both CHIRP and CHIRPS products are significantly better than ARC2 with higher skill and low or no bias. These products were also found to be slightly better than the latest version of the TAMSAT product at dekadal and monthly time‐scales, while TAMSAT performed better at the daily time‐scale. The performance of the different satellite products exhibits high spatial variability with weak performances over coastal and mountainous regions.

Within the last few days, heavy downpour has been experienced in many parts of the Juba and Shabelle River basins both in Somalia and in the Ethiopian Highlands. Flash floods have been reported in some areas within the basins including Gedo, Bakool and Bay regions. Following the heavy rains, the river  levels have increased drastically in the entire reaches of the two rivers and are a few centimeters to reach the bank full levels at Luuq and Belet Weyne. The rainfall forecast for the next seven days (23 to 29 April, 2018) is pointing towards moderate to heavy rains  within the Ethiopian highlands  and inside Somalia.  Observed river levels along the  Juba and Shabelle Rivers are expected to continue rising further in the coming week following the foreseen heavy rains. There is therefore an immediate high risk of flooding along the two rivers given the current situation. Areas to watch include; Belet Weyne and Jowhar towns (Shabelle) and their environs; where the river levels are currently at full crest, Dollow , Bardheere and Bualle town (Juba) and their environs, Other riverine towns in the Middle and Lower Shabelle regions such as Balcaad and Kurtunwaarey as well as those in Lower Juba. Flash floods in Bay and Bakool regions also cannot be ruled out given the rainfall forecast.

During the week ending on 24 April 2018, the Juba and Shabelle basins in Somalia and in the Ethiopian highlands continued to receive moderate to heavy rains. The high rainfall amounts received over the last week were spread across many parts of the country, as indicated in the total Satellite Rainfall Estimates (RFE) in Map1, with the exception of Puntland where light rains were experienced. Following the moderate to heavy rains flash floods and riverine flooding have been reported in many places within the Juba and Shabelle river basins. The prediction for the coming week (Map 2, valid until 01 May 2018) is a forecast of heavy rains in the Juba and Shabelle basins, both inside Somalia and within the Ethiopian highlands. Other central and northern parts of the country will also receive moderate to high rains in the coming week, according to the forecast. Given the forecast and the current high river levels riverine flooding is likely to continue in the coming week. Flash floods are also likely to occur in low lying build up areas especially in Mudug, Bay and Bakool regions during the forecast period.

Enhanced rains are foreseen in the coming week in many parts of the country with Bay and Bakool regions in the south expected to record the highest amounts of rainfall. The Ethiopian highlands will also continue to receive good rains during the period in forecast. The foreseen moderate to heavy rains are likely to exacerbate ground conditions, and trigger additional floods. Built up and low Lying areas of Bay and Bakool will experience flash floods while river flooding along the Juba and Shabelle Rivers will continue.

Moderate to heavy rains have been received in many parts of the country over the last two days. Flash floods have been reported in many places including Bakool, Hiraan and Middle Shabelle regions. The rainfall forecast for the coming week is pointing towards moderate to heavy rains. Low lying areas and built up areas may experience flash floods during the week. River levels along the Juba and Shabelle are expected to continue rising. There is a high risk of flooding in Middle and Lower Shabelle regions following the dramatic river level increase in he last 48 hours. No flooding risk is foreseen along the Juba River during the period under review.

The last 24 hours saw light to moderate rains in a few pockets of the southern and central regions of Somalia. The three days rainfall forecast is pointing towards moderate rains in the southern regions and parts of Galduud and Muddug regions. The Ethiopian highlands may also receive moderate rains within the three days. The seven days rainfall forecast indicates increased rains both in the Ethiopian highlands and southern regions of the country as the week progresses. Given the rainfall forecast, the river levels are expected to continue rising gradually in the coming week with no risk of flooding along the Juba and Shabelle Rivers in Somalia.

The Gu 2018 (April to June) rainfall forecast points towards near-normal to below-normal rains within the Juba and Shabelle River basin. However, flooding along the two rivers is likely to occur, especially in areas with open river banks/weak river embankments. FAO SWALIM (Somalia Water and Land Information Management) has updated the status of the river breakages along the Shabelle River and is in the process of updating the Juba by mapping them using available Very High Resolution (VHR) satellite imagery and a Digital Elevation Model (DEM); supported by “ground truthing” field observations where feasible. All the observations reported refers to the latest suitable VHR satellite image available, which is indicated in the online database. Four types of breakages have been identified, namely; open, potential, closed with sandbags and closed. The open breakages are those that are still open as observed on the latest VHR image available, therefore field verification is needed before planning any repair. The potential breakages represent points that have weak river embankments. The closed with sandbags points are defined here as those that been temporarily closed with sandbags making them still vulnerable for further breakages. The closed points are those that were previously open but have since been closed using heavy machinery or other methods, which prevents further flooding in the short term. The attached map show the open, potential and closed with sandbags points along the Shabelle River. In summary, 27 open points were identified long the river. Several other points, which are either potential or temporarily closed with sandbags, have been identified. The methodology is biased towards Remote Sensing (RS) interpretation with only limited “ground truthing” due to access constraints. Open breakages might have been omitted in some cases where satellite images may not have been very clear (e.g. heavy cloud cover) or were not available. Maps of the status of river breakages, with detailed information, have been produced at large scale and can be obtained from SWALIM offices. This information is also available on the SWALIM Flood Risk and Response Management Information System portal.

As part of flood preparedness and contingency planning, the FAO Somalia Water and Land Information Management project (SWALIM) has finalized mapping of river breakages along the Juba River using Very High Resolution (VHR) satellite images. The middle and lower parts of the river are most vulnerable to flooding. Three types of breakages have been identified namely; open (37), potential (191) and closed with sand bags (21). The open breakages are those that were still open during the period of investigation. The potential breakages represent points that have very weak river embankment or have experienced several breakages in the recent past. The closed with sand bags breakages are those that were previously open but efforts have been made to close them although they are still at risk. The open river breakages pose an immediate danger and high risk of flooding.

While the Gu season is yet to start in Somalia, light to moderate rains were reported in parts of Somaliland since the last week of February and first week of March. The upper parts of the Ethiopian highlands also recorded moderate rains during the last two weeks which led to slight increase of river levels along the Juba and Shabelle Rivers inside Somalia. Light rains are foreseen in a few pockets of Bay and Bakool regions as well as western parts of Somaliland and the Ethiopian highlands in the coming three days (Map 1). The rains are then expected to intensify in space and quantity towards the end of the week (Map 2). Given the rainfall forecast, the river levels are expected to rise with no risk of flooding. Users are advised that this is a forecast and at times there may be discrepancies between forecast and actual amounts of rainfall received.

The last few days saw light rains in some parts of northern and southern regions in the country. The three days rainfall forecast is pointing towards minimal rains with light showers expected in a few pockets of Sool, Gedo, Middle Juba and the southern coastal areas. The seven days rainfall forecast indicates increased rains both in the Ethiopian highland and southern regions of the country as the week progresses. Given the rainfall forecast, the river levels are expected to continue rising gradually in the coming week with no risk of flooding along the Juba and Shabelle Rivers in Somalia.

Most areas across Somalia remained dry over the last three days, apart from light rains reported in few pockets in Somaliland, and light to moderate rains in parts of Bay region. On 14 March areas surrounding Baidoa town reported some rainfall, while in Buur Hakaba 21mm of rain was recorded same day. The upper parts of the Ethiopian highlands continued to receive light to moderate rains over the last week. Minimal rainfall events are foreseen across Somalia in the coming three days (Map 1); while moderate to high rains are expected in parts of Bay, Bakool and Gedo Regions towards the end of the coming week (Map 2). Given the rainfall forecast, the river levels are expected to remain stable over the coming week with no risk of flooding.

The last few days saw increased rainfall activities in some parts of northern and southern regions of Somalia. The three days rainfall forecast points towards moderate rainfall in parts of Togdheer, W. Galbeed, Middle Juba and Gedo regions with light showers in a few pockets across the country. The seven days rainfall forecast indicates increased rains both in the Ethiopian highland and across Somalia as the week progresses. Given the rainfall forecast, the river levels are expected to continue rising gradually in the coming week with no risk of flooding along the Juba and Shabelle Rivers in Somalia. Users are advised that this is a forecast and at times there may be discrepancies between forecast and actual amounts of rainfall received.

The Gu rainy season occurs in the period between March and June and is marked as the primary cropping season in Somalia. The season starts and ends at different times throughout the country. In the areas bordering Kenya, Middle Juba, northern parts of Middle Shabelle and the northwest corner of the country, the Gu rains starts as early as the second half of March. The rains then intensify in April all over the country. The length of the season also varies across the country from year to year. Minimal rainfall events are foreseen across Somalia in the coming three days with Gedo and Bakool regions expected to record moderate rains. The rains will then spread further in the other southern regions in the course of the week with light to moderate intensity. Given the rainfall forecast, the river levels are expected to remain stable over the coming week with no risk of flooding along the Juba and Shabelle Rivers in Somalia.

The Greater Horn of Africa Climate Outlook Forum (GHACOF) has confirmed a reduction of the chances of experiencing a La Nina event during the March to May rainy season. During the recent GHACOF, the March to May 2018 rainfall forecast for the region was released. According to the forecast, Gu 2018 season in Somalia is expected to be normal (40% probability of normal rains) with a tendency of 35 % probability of below normal rains in most parts of the country. This also includes part of the Ethiopian highlands which contribute significantly to both Juba and Shabelle river flow inside Somalia and all inland parts of the country. Further, Awdal , northern parts of Sanaag and Bari regions in the north as well as the southern coastal regions of Lower Juba and Lower Shabelle are expected to experience normal rains (40% probability of normal rains) with a tendency of 35% above normal rains.. The expected depressed rains in many parts of the country will only exacerbate the existing drought conditions. Togdheer, Sool , Nugal and Mudug regions will be worst affected owing to the prevailing drought conditions. Gedo, Bakool, Hiraan and parts of Bay will also be affected adversely by the below normal rains. This outlook is a consensus forecast designed for a regional audience that addresses the rainfall totals summed over the three-month period from March to May 2018. However, SWALIM and other technical partners will keep updating this forecast  for shorter lead time periods and will share with you through the regular bulletins throughout the rainfall season. For more information, please find attached the Somalia Gu 2018 rainfall outlook bulletin.

The Shabelle River which is one of the two perennial rivers in Somalia has had some sections of the channel getting dry for the third time in three years. The first being February and March 2016, then February and March 2017 and finally some sections dried early December 2017 to Mid-March 2018. The Gu rains are expected to kick off in late March and early April within the basin and this will see a rise in river levels. While there are many reasons behind the drying river bed, the main driver to this could be attributed to consecutive failed rainy seasons both in the Ethiopian Highlands and inside Somalia. Rainfall analysis indicates depressed rains during the Deyr seasons of 2015, 2016 and 2017. The poor rains, and increased agricultural water use led to significant reduction of river flow. Massive sedimentation on the river bed has also resulted in decreased water quantity and quality along Shabelle River. Some reports attribute the flow reduction to riverine activities in Ethiopia where the river originates. SWALIM has analysed the temporal river level status using observed river level data and very high-resolution satellite images taken on different dates in selected towns along the Shabelle River. The analysis of multi-temporal images performed by visual estimation of the water levels covers the period from January 2017 to January 2018. The most suitable cloud free images used are panchromatic black and white acquired by the World View 1 satellite. The readability of panchromatic images is more difficult, but generally water is displayed in a dark grey colour, while bare soil is represented by a light grey colour. In addition SWALIM analyzed the vegetation conditions using the Enhanced Vegetation Index (EVI) for December 2001 and December 2017. The selection of these two periods was informed by observation of similar rainfall/vegetation trends in the previous months. This analysis shows a great increase of active irrigated crops upstream (Belet Weyne) in 2017, a slight increase in Bulo Burti and clear decrease in Jowhar (downstream), which could be explained with a progressive increase of water abstraction upstream, affecting the Shabelle river level downstream.

Recurrent flooding along the Shabelle River in Southern Somalia has been one of the key challenges for agencies involved in community development in the area. The Shabelle River is worst affected owing to the topography of the area, uncontrolled irrigation activities and poor river basin management following the collapse of pre-war flood control infrastructure. The Gu 2018 rainy season which was characterised by heavy rains inside Somalia and the Ethiopian highlands led to a significant increase of river levels subsequently leading to river flooding that caused agricultural and economic damage in the Shabelle river basin. SWALIM, has been involved in analysing and mapping the river breakages along the Shabelle River using very high resolution (sub meter) satellite imagery and a Digital Elevation Model (DEM) derived from earlier acquired aerial photographs having 3 meter resolution. Four types of breakages have been identified along Shabelle River namely; Open, Overflow, Potential and Closed. The open breakages are those that were still open during the month of July 2018. The Overflow, indicates points where there has been recent river spillage causing extensive flooding. The potential breakages represent points that have very weak river embankments or have experienced several breakages in the recent past. The closed breakages are those that were previously open but efforts have been made to close them either with sand bags or heavy machinery. The attached table provides locations of both Open and Overflow points along the Shabelle River which require immediate attention. A total of 50 Open points have been identified which is 100% increase from the previous assessment carried out in March 2018 (Refer to the attached table for estimated width of the open breakages). The sharp increase is due to the heavy rains of Gu 2018 rainy season that led to river breakages. 126 Overflow (Overbank river spillage) points have also been identified. The estimated cumulative length of the Overflow sections along the river bank is approximately 82.6 km whose calculation is derived from visible spillages and fresh sand deposits during the flooding period. Several other points, which are either potential or temporarily closed with sandbags, have also been identified. With the Deyr rains expected in October and November 2018, river levels will increase with a likelihood of flooding especially where open and overflow points have been identified. There is therefore an immediate need to close the open points and reinforce areas where there are weak river embankments. Maps of the status of river breakages, with detailed information, have been produced at large scale and hard copies can be obtained from SWALIM offices or by email request through [email protected] It is worth noting that the methodology is biased towards Remote Sensing (RS) interpretation with only limited “ground truthing” due to access constraints. Open breakages and overflows might have been omitted in some cases where satellite images were not available or may not have been very clear due to heavy cloud cover.

Light rains continued to be observed in a few places across the country within the last few days. The cumulated rainfall forecast for the coming three days shows an expected increase of rainfall activities especially in Mudug, Galgadud, Hiraan, Bay and Bakool regions of Somalia and the Ethiopian highlands. The intensity of the rains is expected to spread further in space and quantity as the week progresses given the 7 days rainfall forecast. Consequently, river levels are expected to rise further with a moderate risk of flooding in middle and lower reaches of both Juba and Shabelle Rivers towards the end of the week. Flash floods may also occur in areas where the forecast indicates high rainfall. Users are advised that this is a forecast and at times there may be discrepancies between forecast and actual amounts of rainfall received. The forecast, observed river levels and rainfall amounts are updated on a daily basis and can be found on this link: http://systems.faoso.net/frrims/

The last 24 hours have seen moderate to heavy rains in many parts of the central and southern regions. Today morning, Baidoa and Bulo Burti stations recorded the highest amounts of 124mm and 119mm respectively. Other stations that recorded heavy rains include Bardheere (65mm), Wanle Weyne (52mm), and Mataban (40mm) among others. Heavy rains in Baidoa town and the surroundings led to flash floods and destruction of property. The heavy rains are expected to continue in the next seven days. River levels are expected to continue rising with a moderate to high risk of flooding along the Juba and Shabelle Rivers. Flash floods may also occur in areas where the forecast indicates high rainfall.

The last few days continued to record good rains in many parts of the southern and central regions of Somalia while the northern regions remained relatively dry. The good rains are expected to continue in the next seven days. With a reduction of intensity and spatial distribution towards the end of the week. River levels are expected to continue rising with a moderate to high risk of flooding along the Juba and Shabelle Rivers. Flash floods may also occur in areas where the forecast indicates high rainfall.