Satellite Images Profile Snowfall In Atacama Desert
By Mark Dunphy
One of the driest spots on earth experienced its heaviest snowfall in almost two decades this week, according to the Chilean Directorate of Meteorology (DMC).
A cold front brought up to 80 centimetres (31.5 inches) of snow to the Atacama desert region of South America forcing emergency services to close local roads and rescue dozens of motorists from their vehicles. The temperature in the Chilean capital, Santiago, dropped below minus 8c on Wednesday. Neighbouring Argentina and Uruguay also experienced subzero temperatures.
Located in the north of Chile, the Atacama Desert records less than 50mm of rain on average each year. Some weather stations in the region record only 1-3mm of rain each year. The desert is, according to NASA, National Geographic and many other publications, the driest desert in the world, due to the rain shadow on the leeward side of the Chilean Coast Range, as well as a coastal inversion layer created by the cold offshore Humboldt Current.
Ordinarily, flashes of white rise from salt pans in South America’s Atacama Desert. But on July 7, 2011, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite acquired theses images, the white came from a far rarer commodity: snow. A cold front dumped up to 80 centimeters of snow (32 inches) on the desert, reported BBC News. These images show the rare snowfall.
The top image provides a photo-like, natural color view of the snow. A few clouds hang over the white desert, marring the view slightly. The lower image, which includes both visible and infrared light, helps distinguish between snow and clouds. Snow is dark red, while clouds are lighter shades of orange and white.
According to the website explore-atacama.com, the current wintry conditions are unusual in the region: “In winter (June, July and August) the average daytime temperature is 22°C (72°F) and by night 4°C (39°F), descending to -2°C (28°F) in extreme cases. During summer (January, February and March) the temperature fluctuates between 27°C (81°F) and a minimum of 16°C (61°F) at night, reaching maximums of 32°C (90°F)”.