Travel Guide Witsand Nature Reserve

This 3,300-hectare provincial reserve protects one of South Africa's natural curiosities: dunes measuring between 20 and 60 m in height, grouped together in a 9 x 4 km massif in the middle of a vast plain dominated by the Langberg mountains. From a distance, they look like gigantic piles of sand abandoned there by a mischievous genius. The mystery is amplified by the extreme whiteness of some of the dunes and by the whistling sounds that occur under special weather conditions, usually in summer. Only around thirty "singing" dune sites have been identified worldwide. In 2002, two CNRS researchers published the results of their study of such dunes in Morocco. Stéphane Douady and Pascal Hersen describe the phenomenon known as "Reynolds dilation", a pulsation that causes the air to vibrate, generating an acoustic wave. the song of the dunes appears when the sand is in motion," explains Pascal Hersen, "when an avalanche breaks out on the steepest slope of the dune The French have measured very powerful songs, around 100 decibels, with harmonics at 200, 300 or 400 hertz. As for Witsand, it's a mystery! Extremely well-maintained reserve: picnic, swimming pool, birdwatching, botanical trails, bike hire.