World's driest desert sees huge snowfall

Friday 08th Jul 2011 by theWeather club

We have got used to hearing about extremes of weather around the world. If fact we are becoming so used to hearing about ‘unusual weather’ that it appears to becoming commonplace. Even the weather presenters now explain the latest ‘unprecedented’ event with less of a sense of surprise as they once did. However the latest strange weather event would halt even the most jaundiced weather folk in their tracks. The Atacama Desert – one of the driest places on the planet – a place so dry it makes other deserts look like swampland, has just been buried under 80 centimetres of snow, according to the Chilean Directorate of Meteorology.

To put this in perspective, there are parts of the region that record between 1-3mm of rain each year, and there are some weather stations that have never seen any rain at all. Ever. It is considered by many meteorologists to be the driest desert in the world. The arid nature of the desert is caused by its location in the rain shadow of the Chilean Coast Range of mountains.  On top of this Humboldt Current  - a cold, low-salinity ocean current that flowing along the west coast of South America – cools the marine air thus reducing the amount of rain that would otherwise be generated.

Then there is the temperature. In the winter months June, July and August the average daytime temperature is 22°C falling to 4°C at night, sometimes going down as far as -2°C in extreme cases. Cold but hardly blizzard temperatures.

The snowfall was caused by cold front that has brought freezing temperatures to parts of South America. Emergency services in the region have been forced to close local roads, to prevent more people getting into difficulties as they rescued dozens of motorists trapped by the sudden snowfall.  The temperature in the Chilean Santiago fell to -8°C at one point, and there were also reports of parts of Argentina and Uruguay being hit by freezing temperatures.

So no matter how well we think we know the what to expect, nature maintains the ability to surprise, as nearly a metre of snow falling in this hot arid wasteland clearly demonstrates.