2023-09-14 22:05:00
(CNN) — It all started with an explosion at 3:00 am on Monday, when the inhabitants of Derna were sleeping. One dam burst, and then a second, generating a huge wave of water that rushed from the mountains to the city on the Libyan coast, killing thousands of people as entire neighborhoods were swept into the sea.
At least 5,000 people died in Libya in this week’s floods, Doctors Without Borders (Médecins sans frontières) said in a statement released Thursday, in the deadliest flood disaster in Africa since records began more than a century.
The city of Derna, in eastern Libya, the epicenter of the disaster, had a population of around 100,000 before the tragedy. Authorities say at least 10,000 remain missing. CNN could not independently verify the figures.
Buildings, homes and various infrastructure were “swept away” when a seven-meter wave hit the city, according to the International Committee of the Red Cross (ICRC), which said Thursday that bodies were reappearing in the coastal city.
But with thousands dead and many more still missing, questions are emerging about why the storm that also hit Greece and other countries caused so much devastation in Libya.
Experts say that apart from the severe storm itself, the Libya catastrophe was greatly exacerbated by a deadly confluence of factors including aging, deteriorating infrastructure, inadequate warnings and the impacts of the accelerating climate crisis.
A fierce storm
The extreme rains that hit Libya on Sunday were caused by a system called Storm Daniel.
After ravaging Greece, Turkey and Bulgaria, with severe flooding that killed more than 20 people, it became a medican over the Mediterranean: a relatively rare type of storm with characteristics similar to hurricanes and typhoons.
The Medican strengthened as it crossed the unusually warm waters of the Mediterranean before bringing torrential rains over Libya on Sunday.
It brought more than 414 mm of rain in 24 hours to Al-Bayda, a city west of Derna, setting a new record.
While it is too early to definitively attribute the storm to the climate crisis, scientists believe that climate change is increasing the intensity of extreme weather events like storms. Warmer oceans provide the fuel for storms to grow, and a warmer atmosphere can hold more moisture, which means more extreme precipitation.
Storms “are becoming more ferocious due to climate change,” said Hannah Cloke, a hydrology professor at the University of Reading in the United Kingdom.
A story of floods
Derna is prone to flooding and its dam reservoirs have caused at least five deadly floods since 1942, the last of which occurred in 2011, according to a research article published by Libya’s Sebha University last year.
The two dams that collapsed on Monday were built about half a century ago, between 1973 and 1977, by a Yugoslav construction company. The Derna Dam is 75 meters high and has a storage capacity of 18 million cubic meters. The second dam, Mansour, is 45 meters high and has a capacity of 1.5 million cubic meters.
Floods in the city of Derna, in eastern Libya, this Tuesday. Credit: Jamal Alkomaty/AP
These dams have not received any type of maintenance since 2002, he told Al Jazeera the city’s vice mayor, Ahmed Madroud.
But problems with dams are not new. The Sebha University paper warned that the Derna dams had a “high flood risk potential” and that regular maintenance was needed to prevent “catastrophic” flooding.
“The current situation at the Wadi Derna reservoir requires officials to take immediate measures to carry out regular maintenance of the existing dams,” the document recommended last year. “Because in the event of a major flood, the result would be catastrophic for the inhabitants of the valley and the city.” He also found that the surrounding area lacked adequate vegetation capable of preventing soil erosion. Residents in the area should be aware of the dangers of flooding, he added.
Liz Stephens, professor of Climate Risk and Resilience at the University of Reading in the United Kingdom, told CNN there were serious questions about the dam’s design standard and whether the risk of very extreme rainfall had been adequately taken into account.
“It’s very clear that without the dam breaking, we would not have seen the tragic number of deaths that occurred as a result,” he said.
“The dams would have held back water initially, and their failure would have potentially released all the water at once,” Stephens also told the Science Media Center, adding that “debris trapped in the flood waters increased the destructive power.” .
Derna has suffered in the past from the ravages of years of fighting and the destruction of its infrastructure.
Since the fight against ISIS and then against eastern commander Khalifa Haftar and his Libyan National Army (LNA), the city’s infrastructure has been crumbling and is woefully inadequate in the face of flooding such as that caused by Storm Daniel.
Lack of warnings
Better warnings could have prevented many of the casualties in Derna, said the head of the United Nations World Meteorological Organization, Petteri Taalas.
“If there had been a normally functioning weather service, warnings would have been issued and also emergency management would have been able to carry out evacuations to avoid most of the human casualties,” Taalas told reporters at a news conference on Thursday.
Talaas added that political instability in the country has impeded efforts by the World Meteorological Organization (WMO) to work with the Libyan government to improve these systems.
However, even strong early warning systems do not guarantee that all lives can be saved, Cloke said.
Dam failures can be very difficult to predict and are fast and fierce, he told CNN. “We have this monstrous volume of water that can wipe out the entire city,” Cloke said. “It’s one of the worst types of flooding that has ever happened.”
While dams are typically designed to withstand relatively extreme events, it is often not enough, Cloke said. “We should prepare for unexpected events and then put climate change first, and that intensifies these unexpected events.”
The risk that climate-driven extreme weather poses to infrastructure – not just dams, but everything from buildings to water supplies – is global. “We are not prepared for the extreme events that are coming,” Cloke said.
CNN’s Celine Alkhaldi, Mostafa Salem and Sharon Braithwaite contributed to this report.
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