April 27, 2024

Deadly Cyclonic Catastrophe: Once-in-600-Year Storm in Libya Swept Entire Neighborhoods Out to Sea

A September 2023 cyclone seriously impacted Libyas northeastern coast, particularly the city of Derna. Thousands died, and 40,000 were displaced. Satellite images highlighted the enormous damage, with the storm being classified as one of Africas deadliest and rarest weather events.
Flash floods in the port city damaged roadways and swept communities out to sea.
Heavy rain from a cyclone in the Mediterranean swamped cities along the northeastern coast of Libya in early September 2023, triggering thousands of deaths. The port city of Derna (Darnah), home to about 90,000 individuals, was among the worst struck by the storm and suffered extensive flooding and damage.
On September 10 and 11, over 100 millimeters (4 inches) of rain fell on Derna. The city lies at the end of a long, narrow valley, called a wadi, which is dry except during the rainy season. Floods triggered 2 dams along the wadi to collapse. The failure of the second dam, situated simply one kilometer inland of Derna, released floodwater 3-7 meters (10-23 feet) high that tore through the city. According to news reports, the flash floods destroyed roadways and swept whole areas out to sea.
Satellite image of Libyas northeastern coast recorded on August 25, 2023, by the Operational Land Imager-2 on Landsat 9.
The images on this page reveal the city before (above) and after (listed below) the storm. The image below, acquired by Landsat 9s Operational Land Imager-2 (OLI-2) on September 18, reveals worn down banks of Wadi Derna near where it meets the Mediterranean. Water just off the coast appears muddier than in the image above, which shows the very same location on August 25 and was acquired by Landsat 8.

A September 2023 cyclone severely impacted Libyas northeastern coast, particularly the city of Derna. The failure of the second dam, located just one kilometer inland of Derna, released floodwater 3-7 meters (10-23 feet) high that tore through the city. The images on this page show the city before (above) and after (listed below) the storm. The image listed below, gotten by Landsat 9s Operational Land Imager-2 (OLI-2) on September 18, shows deteriorated banks of Wadi Derna near where it meets the Mediterranean.

Satellite picture of Libyas northeastern coast captured on September 18, 2023, by the Operational Land Imager on Landsat 8.
Preliminary price quotes by the United Nations Satellite Center (UNOSAT) show that 3,100 buildings in Derna were harmed by hurrying water. According to the UN International Organization for Migration (IOM), about 40,000 people in the country were displaced by the storm, and 30,000 of those were displaced from Derna.
Tropical-like cyclones in the Mediterranean, or “medicanes,” develop just when or two times a year, according to NOAA, and generally form in autumn. According to meteorologists at Yale Climate Connections, this storm was the deadliest in Africas recorded history. A current evaluation by scientists at World Weather Attribution approximated that precipitation received by the region was a one-in-300 to one-in-600-year event.
NASA Earth Observatory images by Lauren Dauphin, utilizing Landsat information from the U.S. Geological Survey.