13, September, 2023
More than 5,300 people died after floods burst two dams in the eastern city and swept away homes.
Speaking to the BBC's Today programme, Johr Ali said survivors had reported scenes of utter devastation.
He said entire families had been washed away by powerful waters. One friend found his "nephew dead in the street, thrown away by water from his rooftop".
The reporter - who lives in exile in Istanbul because of attacks on journalists in Libya - said another friend of his had lost his entire family in the disaster.
"I was next to him, I heard the news of the deaths of [his friends'] full family," Mr Ali recalled.
"His mother, his father, his two brothers, his sister Maryam, and his wife - his newly married wife - who he sent to Libya to visit his family just two weeks ago, and his little kid who is eight months old.
"All of those died, all of his family is dead, and he is asking me what should I do."
In another case, Mr Ali said a survivor had told him of witnessing "a woman hang from the streetlights, because she was taken away by the floods and she was hanged from the streetlights".
"She stayed and died there," Mr Ali added.
The port city had a population of around 90,000 people before this week's disaster. Officials say it is feared that around 10,000 remain missing, with some simply washed away by powerful flood waters into the Mediterranean Sea.
Streets in Derna are covered in mud and rubble and are littered with upturned vehicles. Mr Ali said that of the city's 10 geographical districts, just three had survived the flooding.
He added that a constant soundtrack of the cries of young children now engulfed the city.
Meanwhile, scores of people and relief workers are scouring Derna for survivors, with many feared to be trapped underneath collapsed buildings.
"People are hearing the cries of babies underground, they don't know how to get to them," Mr Ali reported.
"People are using shovels to get the bodies from underneath the ground, they are using their own hands. There are photos of the city of people getting bodies out with their naked, bare hands.
"The situation is beyond catastrophic."
Libya is divided between two rival governments - with the interim, internationally recognised government operating from Tripoli and a rival one in the east.
The disaster has prompted rare displays of cooperation between the competing powers. On Tuesday aid planes carrying medical supplies were sent to the eastern city of Benghazi from Tripoli.
But partisan lines remain starkly drawn elsewhere, with Khalifa Haftar - commander of the self-styled Libyan National Army that controls the east - ignoring international pledges of support from allies of the western, Tripoli-based authorities.
Mr Ali was quick to condemn both regimes, who he said were failing to react effectively enough.
"Sadly the country is divided between two governments, and sadly those two weak, unqualified governments didn't get the help that people need," Mr Ali told the BBC.
And while the UN has pledged to support relief efforts, and the Red Cross says its teams are active on the ground, Mr Ali said that only minimal supplies had managed to reach survivors.
"On the ground, only help from Turkey came to the city of Derna, and only in small scale," he said.
"There are lots of people without shelters, without food, without clean water. People themselves are trying to help each other.
"What we need right now is a huge scale, big scale international support that should come immediately to come and help the people."