A tsunami-sized flash flood broke through two ageing river dams upstream from the coastal city after the Mediterranean Storm Daniel lashed the area on September 10.
It razed entire neighbourhoods, sweeping untold thousands of people into the sea.
The official death toll stands at more than 3,300 – but the eventual count is expected to be far higher, with international aid groups giving estimates of up to 10,000 people missing.
“An estimated 43,059 individuals have been displaced by the floods in northeastern Libya,” the IOM said, adding that a “lack of water supply is reportedly driving many displaced out of Derna” to other areas.
“Urgent needs include food, drinking water and mental health and psychosocial support,” it said.
Mobile and internet services were meanwhile restored after a two-day disruption, following protests Monday that saw angry residents blame the authorities for the high death toll.
Authorities had blamed the communications outage on “a rupture in the optical fibre” link to Derna, but some internet users and analysts charged there had been a deliberate “blackout”.
Tripoli-based Prime Minister Abdulhamid Dbeibah announced that communications had been restored in the east, in a post on X, formerly Twitter, on Thursday.
War-scarred Libya remains split between Dbeibah’s UN-backed and nominally interim government in the west, and another in the disaster-hit east backed by military strongman Khalifa Haftar.
