A Few Points You Should Know About Sand Dunes But Had Been Afraid To Ask
Walvis Bay Namibia, is a coastal town situated right on the edge of the Namib Sand Sea. This is made up of a few large tracts of sand dunes which lie along the coastal region.
The image of the landscape of this particular area between Luderitz and Walvis Bay, is possibly how most people think of Namibia, the pictures of massive sand dunes are quite impressive and are photographed and published often.
This area befittingly known as the sand sea, contains different types of dunes, mainly barchan dunes and transverse dunes and covers an area roughly 400 kilometres in length and is between 150 and 100 kilometres in width.
Sand dunes have two very different sides depending on where the wind comes from, the windward side of a barchan dune is at an angle of more or less 15 degrees, while the other side, the slip face, is at a much steeper angle of 32 degrees, the barchan dune is more or less arc shape and has two long sides joined by the curved piece at the top forming the arc.
As with most sand dunes, there is an enormous variation in size, they range from hundreds of metres to just a few metres.
The action of the wind constantly blowing into the sand causes the dune to migrate by the sand getting blown up the windward side and then it falls ofer down the slip face side, so it is constantly moving along very gradually.
Due to the varying amounts of sand in differnt size dunes, smaller ones move at a faster rate than large ones, this can cause the smaller ones to sometimes appear as if they are cutting into the larger dunes, and they eventually overtake the bigger ones.
Inland areas are covered with linear dunes, which run approximately north to south, while nearer the coast, the transverse dune is commonplace. The transverse dune is positioned around 90 degrees to the prevailing wind with a gentle slope on the windward side and a much steeper leeward slope
These dunes have some vegetation in the form of grasses growing on them, while the more mobile dunes nearer the coast have almost no vegetation whatsoever, but do have a rich variety of small insects and other small animals.
They say that there is a very similar type of dune to the barchan dune here and you can find it on Mars due to there being strong winds blowing, acting in a similar way with the sand and dust up there. But that’s another story.
The next time you march across these sand hills, you’ll certainly want refreshment. Just head here Walvis Bay
