Bob Henson and Jeff Masters write:

Africa’s deadliest storm in recorded history struck eastern Libya on Sunday and Monday, leaving thousands dead and an already struggling society faced with a mammoth recovery effort. Storm Daniel’s preliminary death toll of 5,300 in Libya as of Wednesday morning surpasses the 1927 floods in Algeria (3,000 killed) as the deadliest storm in Africa since 1900, according to statistics from EM-DAT, the international disaster database. Storm Daniel is also the deadliest storm globally since at least 2013 when Super Typhoon Haiyan killed 7,354 people in the Philippines.

The worst flooding from Storm Daniel was in the port city of Derna (population 90,000), where the failures of the nearby Derna and Abu Mansur dams, both about 50 years old, allowed a wall of water to rip through the heart of town along the Wadi Derna, which is a dry riverbed during much of the year. Carving a path some 100 meters (320 feet) wide, the floodwaters inundated some buildings and caused others to collapse.

The Libya flood disaster was driven in part by the meteorological bad luck of Daniel coming ashore directly atop a compact zone of higher elevation. That’s only part of the story, though. Human-induced climate change is loading the dice, enhancing the ability of tropical cyclones and similar storms to produce extreme rain as they draw more water vapor out of oceans into a warming atmosphere.

The Mediterranean Sea has warmed by an average of roughly 2 degrees Celsius (3.6°F) over the past 40 years. This summer the daily average sea surface temperatures of the Mediterranean hit new records for July (topping 28 degrees Celsius or 82°F for the first time in any month) as well as for August, according to the Spanish research center CEAM. [Continue reading…]