A severe medicane in September 2023 led to extensive flooding and displacement in northeastern Libya. Satellite images post-disaster revealed widespread power outages, especially in Derna and Al Bayda, with ongoing recovery efforts.
Cities and towns darkened after a cyclone unleashed torrential flooding along the country’s coast.
On September 10, 2023, a powerful storm brought heavy rain to northeastern Libya, causing significant loss of life and devastation to cities along the coast. Data from satellites show that after the storm, many communities in the region had lost electric power.
The storm—a Mediterranean hurricane-like system known as a medicane—brought 414 millimeters (16 inches) of rain to the city of Al Bayda. Nearby, the port city of Derna received more than 100 millimeters (4 inches)—far exceeding the city’s average monthly rainfall for September of less than 1.5 millimeters (0.1 inches).
Flash floods swept away roads and entire neighborhoods, displacing around 40,000 people across the country. Preliminary estimates by the United Nations Satellite Center (UNOSAT) indicate that about 10,000 buildings were damaged by floodwater, although assessment of the damage was still ongoing as of September 22. Infrastructure damage led to power outages, which can be seen in satellite images acquired at night.
Satellite map of light emitted from Libya on September 8, 2023 — before the storm.
Satellite map of light emitted from Libya on September 13, 2023 — after the storm.
The maps above show the amount of light emitted from affected communities in northeastern Libya before and after the storm and the peak of the torrential flooding. The upper map shows the area on September 8, 2023; the lower map shows the same area on September 13, three days after the storm made landfall.
“There was a substantial loss of power evident in the vicinity of Derna and Al Bayda in the September 13 image when compared to the baseline image,” said Ranjay Shrestha of NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is "To discover and expand knowledge for the benefit of humanity." Its core values are "safety, integrity, teamwork, excellence, and inclusion." NASA conducts research, develops technology and launches missions to explore and study Earth, the solar system, and the universe beyond. It also works to advance the state of knowledge in a wide range of scientific fields, including Earth and space science, planetary science, astrophysics, and heliophysics, and it collaborates with private companies and international partners to achieve its goals.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>NASA’s Black Marble science team. The maps come from the Black Marble HD product, provided by Shrestha and Zhuosen Wang, a principal investigator on the science team, and are based on data from the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the NASA-NOAAThe National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States government that is focused on understanding and predicting changes in Earth's oceans, atmosphere, and climate. It is headquartered in Silver Spring, Maryland and is a part of the Department of Commerce. NOAA conducts research and provides information, products, and services that are used to protect life and property, and to support economic growth and development. It also works to conserve and manage natural resources, including fisheries, wildlife, and habitats. Some of the specific activities that NOAA is involved in include weather forecasting, climate monitoring, marine biology and fisheries research, and satellite and remote sensing.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>NOAA Suomi NPP satellite. The basemap was built from data collected by Landsat 8 and Landsat 9 satellites.
Derna was devastated by the storm. Flooding in the city led to the collapse of two dams along a usually dry riverbed, or wadi. The dam failures unleashed 3- to 7-meter-high floodwater that tore through the city, sweeping roads and buildings out to sea.
The city became significantly darker after the storm hit. In a recent report, UNOSAT documented changes in Derna’s brightness. UNOSAT uses Black Marble nighttime light products to support ground teams in disaster response.
Satellite map of light emitted from Derna Libya on September 8, 13, and 18, 2023.
Some communities near Derna went four days without electricity, according to NPR reporting. But by September 18, 2023, the brightness of outdoor lighting in Derna was approaching pre-storm levels. “There’s a lot more recovery compared to the September 13 image,” said Shrestha. “However, there are still pockets of areas, particularly in the outskirts of the Al Bayda area, where recovery seems ongoing.”
Raw, unprocessed images of night lights can be misleading because moonlight, clouds, air pollution, snow cover, seasonal vegetation, and even the position of the satellite, can change how light is reflected. The Black Marble science team processes the data to account for these factors.
NASA Earth Observatory images by Wanmei Liang, using Black Marble data courtesy of Ranjay Shrestha and Zhuosen Wang/NASA Goddard Space Flight Center, Landsat data from the U.S. Geological Survey, and data from OpenStreetMap.
Source: SciTechDaily
