The layout of the city of Derna, on the northeastern coast of Libya, amplified the extreme damage wrought by flooding there over the weekend. The floods have killed more than 5,000 people, according to local authorities, and thousands more are missing.
Derna lies along the coast of the Mediterranean Sea, at the end of a long, narrow natural valley, called a wadi, which is dry for much of the year.
As the port city was inundated by Storm Daniel, which made landfall in Libya on Sunday, the wadi worked as a funnel, forcing the rushing water into the center of the city. Riverbanks swelled, bridges were washed out and two dams farther up the wadi burst, adding their waters to the deluge.
Rescue teams arrived and further supplies were expected Tuesday in the city of Benghazi, some 180 miles from Derna by car, according to Libyan interim government and media sources, but blocked roads posed challenges in getting them to Derna.
Photos taken in Derna show widespread destruction along what is usually a dry riverbed. Numerous bridges were washed out, with only the support structures remaining in place.