Dust Cloud

In the late 1960s, Lake Texcoco remained dry most of the year. During the rainy season, its basin would fill up and spill onto the city, flooding its main streets, although only for a couple of months. The remaining part of the year the ground would dry out. Its grains of dust and salt were exposed to sunlight and wind. This wind would lift the thicker grains and drag them along at ground level, baring the underlying layer. Blowing in all directions, the wind would lift the dust to then thrust it to the ground. Localized explosions of aeolic erosion fractured the soil. When coarser particles hit the ground, finer ones would then rise in huge veils of dust which thickened into veritable walls. The volatile particles of these “walls” rose further, in the shape of clouds. They were manipulated by the softer wind currents and driven back towards Mexico City at very high speeds. These tolvaneras (“dust clouds”) happened around 33 times a year and were as strong as the sandstorms in the Sahara Desert.  [...]

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