With better functioning coordination in the crisis-wracked country, "they could have issued the warnings and the emergency management forces would have been able to carry out the evacuation of the people, and we could have avoided most of the human casualties," Petteri Taalas, head of the U.N.'s World Meteorological Organization, told reporters in Geneva.
His comments came after a tsunami-sized flash flood hit eastern Libya at the weekend, killing at least 4,000 people, with thousands more missing and feared dead.
The enormous surge of water burst two upstream river dams and reduced the city of Derna to an apocalyptic wasteland where entire city blocks and untold numbers of people were washed into the Mediterranean Sea.
Taalas said lacking weather forecasting and dissemination and action on early warnings was a large contributor to the size of the disaster.
The years-long internal conflict wracking the country meant its meteorological "observing network has been very much destroyed, the IT systems have been destroyed," he said.
"The flooding events came and there was no evacuation taking place, because there was not the proper early warning systems in place."
If evacuations had taken place, the human toll would have been far lower, he said.
"Of course, we cannot fully avoid economic losses, but we could have also minimized those losses by having proper services in place," he said.
Libya's National Meteorological Centre (NMC) did issue early warnings for the extreme weather coming 72 hours in advance and had notified governmental authorities by email, urging them to take preventative measures.
But WMO said it was "not clear whether (the warnings) were effectively disseminated."
It said that while there had once been close cooperation between meteorological services and disaster management throughout Libya, this was no longer the case.