Storm Daniel became the deadliest Mediterranean tropical-like cyclone on record, killing over 5,900 people in Libya after two dams collapsed near Derna.
Key Facts
- Deaths (Libya)
- Over 5,900
- Injuries (Libya)
- Over 7,000
- Missing persons
- At least 8,000
- Damage in Greece
- Over 2 billion EUR
- Dams collapsed
- 2 (Derna and Mansour dams)
- Countries affected
- Greece, Bulgaria, Turkey, Libya
By the Numbers
Location
Cause → Event → Consequence
Storm Daniel originated from an omega block weather pattern — a high-pressure zone flanked by two low-pressure systems — around 4 September 2023. This configuration trapped the system, making its path erratic. As it acquired quasi-tropical characteristics, it intensified before striking Libya, where pre-existing civil war damage had left critical infrastructure, including aging dams, in severely degraded condition.
The storm caused catastrophic flooding across Greece, Bulgaria, and Turkey before moving toward Libya. Near Derna, torrential rainfall caused the Derna and Mansour dams to collapse, releasing floodwaters into the Wadi Derna river valley. The resulting deluge devastated the city of Derna, killing over 5,900 people, injuring more than 7,000, and leaving at least 8,000 missing, making it the deadliest Mediterranean tropical-like cyclone in recorded history.
In the aftermath, multiple Mediterranean nations pledged humanitarian and financial aid to affected countries. Libya's catastrophic losses were widely attributed to the deterioration of its infrastructure during years of civil war. Greece suffered over two billion euros in damage, the costliest storm on record for the country. Globally, Storm Daniel ranked as the second-costliest tropical cyclone outside the North Atlantic Basin.