Where Is The Driest Place On Earth?

Antarctica. Parts of the continent have seen no rain f or two million years. A desert i s technically defined as a place t h at receives less than 254 m m (10 inches) of rain a year. The Sahara gets just 25 m m (1 inch ) of rain a year. Antarctica’ s average  annual rain fall is about the same, but 2 per cent of it , known as the Dry Valleys, is free of ice an d snow and it never rain s there at all . The next -driest place in the world is the Atacama Desert in Chile. In some areas, no rain has fallen there for 400 years and its average annual rain fall is a tiny 0.1 m m (0.004 in ch es). Taken as a whole, this makes it the world’s driest desert , 250 times as dry as the Sahara. As well as the driest place on earth , Antarctica can also claim to be the wettest and the windiest . Seventy per cent of the world’ s fresh water is found there in the form of ice, and its win d speeds are the fast est ever recorded. Th e unique conditions in the Dry  Valleys of Antarctica are caused by so-cal led adiabatic winds (from the Greek word for ‘going down ’). These occur when cold, dense air is pulled down hill simply by t h e force of gravity . Th e winds can reach speeds of 320  kph (200 mph ) evaporating all m oi st u re – water, ice and snow – in the process. Though Antarctica is a desert , these completely dry part s of i t are cal led, somewhat ironically , oases. They are so similar to conditions on Mars that NASA used them to test the Viking mission .