I was poking around the CIA World Factbook (doesn’t everyone?) and came across an interesting page that listed "miscellaneous geographic information of significance not included elsewhere." That’s wonderful, I thought, a page of international odds-and-ends that didn’t fit within the book’s prescribed format. I live for moments like that.
It listed little tidbits on just about every nation around the globe. My mind wandered over to the entry for Djibouti:
strategic location near world’s busiest shipping lanes and close to Arabian oilfields; terminus of rail traffic into Ethiopia; mostly wasteland; Lac Assal (Lake Assal) is the lowest point in Africa and the saltiest lake in the world
That’s a lot of miscellany for such a tiny nation, a place slightly smaller than the U.S. state of Massachusetts and populated by fewer than a million residents. I was fascinated by the thought of Lac Assal although seeing a nation described as "mostly wasteland" amused me as well. I’m sure the residents wouldn’t endorse that characterization.
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Sources agree that Lac Assal is the lowest point of elevation in Africa. However, there’s a variation in its recorded altitude which seems to center at about -155 metres (-509 feet) give or take a few metres. Assal is a crater lake on the end of a rift valley formed along a geologic fault. The plates split apart, a volcano created a crater, and a depression formed well below sea level. Any water that finds its way into the valley and the crater has no way to escape. Lac Assal doesn’t have an outlet to the sea.
The salinity has become intense due to minerals eroding from the surrounding terrain that washes down into the lake and remains there, while the water evaporates. This is typical of endorheic basins — the same condition exists in Utah’s Great Salt Lake (my visit). The CIA referred to Lac Assal as the "saltiest lake in the world" and that may be true, although Don Juan Pond in Antarctica is allegedly saltier. Lake? Pond? Whatever. Lac Assal is really salty and it’s a source of industry for the area. Huge salt flats are clearly visible on the northwest side of the satellite image.
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That’s all interesting, however I’m most fascinated by its proximity to the sea. Maybe 10 kilometres separates Lac Assal from Ghoubbet El Kharab (or Lake or Bay of Ghoubet). Take a close look at the eastern edge of Ghoubbet El Kharab. It is connected to the Gulf of Tadjoura by a narrow passageway, which in turn is connected to the Gulf of Aden. Thus, the surface of Ghoubbet El Kharab would be at sea level. The lowest point in Africa is a mere ten klicks away! One narrow ridge of stone is all that separates Africa’s lowpoint from being inundated by the sea.
In fact, Ghoubbet El Kharab is Lac Assal’s main source of water. Certainly whatever rain falls within the basin, as lacking as that may be, would flow into the lake. Much more water seeps through fissures in the stone wall between Ghoubbet El Kharab and Lac Assal. The stone separating the two features acts as a dam with a crack in it.
Youtube, LAC ASSAL / DJIBOUTI by Mheshimiwa73
Tourists visit Lac Assal generally in winter. The temperature can hit 50° Celsius (122° Fahrenheit) in the summer, and become truly life threatening. There are other hazards. Djibouti was involved in a civil war between 1991 and 1994 and matériel still remains scattered throughout the countryside. The United States Embassy issued a security message in 2012 after a boy was injured by a land mine nearby (map). So if you go — and I hope someday some of you do — time it right and stick to the roads. And take lots of photos.