Flood impact assessment in Derna City centre, East Province, Libya

**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 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** This map illustrates satellite-detected flood impact in the 2 Derna dams over Benghazi Governorate, East pronvce, Libya, as observed from optical very-high resolution satellite imagery. Dam wall reservoirs appears to be destroyed in both the upstream and the downstream Derna 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** 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.

**UNOSAT code FL20230912LBY, GDACS Id: 1102204** Live web map showing analysis related to floods in Libya following the strom Daniel in the north-eastern part of Libya.

**UNOSAT code FL20230912LBY, GDACS Id: 1102204** Status: Significant light loss observed. Further action(s): Continuous observations planned for full assessment Severe floods in Libya have generated power supply outage in Derna and Al Baydā. About 5 km2 in Derna, and 4 km2 in Al Baydā became darker based on comparison of SDGSAT-1 images acquired before and after the floods. River delta area in Derna city lost the majority of night-time light, with power supply not fully restored as of 17 September 2023. In Al Baydā, power supply has been almost fully restored as of 17 September 2023. Continuous observations have been planned for full assessment of power recovery.