Flood impact assessment in Derna dams, East Province, Libya

**UNOSAT code FL20230912LBY, GDACS Id: 1102204** This map illustrates satellite-detected flood impact in 4 dams over Benghazi and Almarj governorates, East pronvce, Libya, as observed from optical very-high resolution satellite imagery. Dam reservoirs appears to be filled over the 4 dams. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to the United Nations Satellite Centre (UNOSAT).

**UNOSAT code FL20230912LBY, GDACS Id: 1102204** This map illustrates satellite-detected flood extent in Derna City located in the East Province of Libya, as observed from a Pléiades imagery acquired on 13 September 2023 at 13:39 local time after the passage of the Mediterranean tropical-like cyclone Daniel. Within the city of Derna, at least 2,217 buildings appear to have been exposed to rushing floodwaters. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to the United Nations Satellite Centre (UNOSAT).

**UNOSAT code FL20230912LBY, GDACS Id: 1102204** This map illustrates satellite-detected flood extent in the centre of Derna (Libya) as observed from a Pléiades imagery acquired on 13 September 2023 at 13:39 local time after the passage of the Mediterranean tropical-like cyclone Daniel. Extensive damage and destructions are observed in the city centre and the port area. 2217 buildings were affected by the rushing floodwaters in Derna and 886 in this sector of the city. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to the United Nations Satellite Centre (UNOSAT).

**UNOSAT code FL20230912LBY, GDACS Id: 1102204** Status: increased water observed Further action(s): continue monitoring Wadi Qattarra Dam 1 & 2 appears to be filled as of 16 September 2023; Wadi Jaza dam appears to be filled as of 15 September 2023; Increased water observed in Al Marj dam as of 15 September 2023; Both Derna dams destroyed by rushing flood waters.

**UNOSAT code FL20230912LBY, GDACS Id: 1102204** This map illustrates satellite-detected flood extent in the Al Tamimi Town, East Province (Libya) as observed from a Pléiades imagery acquired on 13 September 2023 at 11:15 local time after the passage of the Mediterranean tropical-like cyclone Daniel. Within the extent of the map, at least 64 structures appear to have been potentially exposed to rushing floodwaters. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to the United Nations Satellite Centre (UNOSAT).

**UNOSAT code FL20230912LBY, GDACS Id: 1102204** On the night of the 10th of September 2023, after its journey through the Mediterranean Sea, the storm Daniel brought heavy rains that triggered floods in Benghazi, Almarj, Al Jabal Al Akhdar and Derna Governorates, in northeastern Libya. The increase of water levels in the region caused the collapse of two dams located upstream Derna River and the consequences was tremendous. The dam breach released a massive amount of water and a huge flood wave wiped out entire neighbourhoods in the city of Derna. Hundreds of people were reported missing by the Libyan Red Crescent Society. According to the Libyan National Meteorological Centre, the storm reached its peak with winds going up to 70-80 km/h. This led to the falling of electricity towers and tress causing communications interruption. Between 150 – 240 mm were reported and caused flash floods in several cities. Al-Bayda have recorded the highest daily rainfall rate: 414.1 mm in the night of the 10 to 11 September 2023.