Look: 7 photos that capture 'catastrophic' scale of destruction after floods kill 11,300 in Libya

Emergency teams on Friday kept up their search for the thousands still posted as missing from the tsunami-sized flash flood that swept the Libyan port city of Derna, killing at least 11,300 people.

The enormous surge of water burst two upstream dams late Sunday and reduced Derna to an apocalyptic wasteland where entire city blocks and untold numbers of people were washed into the Mediterranean (see photo above).

Calling the situation "catastrophic", the United Nations launched an appeal for more than $71 million to respond to the "most urgent needs of 250,000 people targeted out of the 884,000 people estimated to be in need".

UN humanitarian agency OCHA estimates suggest 30 percent of the city may have disappeared and with most roads collapsed local authorities are calling for a sea corridor to be established for relief and evacuations.

This combination image of satellite photos shows a coastal road before (top) and after the storm.

An AFP journalist in Derna said central neighbourhoods on either side of the river, which normally dries up at this time of year, looked as if a steam roller had passed through, uprooting trees and buildings and hurling vehicles onto the port's breakwaters.

The entire seaside town of Sousse meanwhile remains submerged.

"Entire neighbourhoods have been wiped off the map. Whole families, taken by surprise, were swept away in the deluge of water," OCHA head Martin Griffiths said in a statement. This is what Derna city looks like on the ground.

The United Nations said Thursday that most of the thousands of deaths in Libya's flood disaster could have been averted if early warning and emergency management systems had functioned properly.

Access to Derna remains severely hampered as roads and bridges have been destroyed and power and phone lines cut to wide areas, where at least 30,000 people are now homeless.

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