The snowfall in hot deserts are unusual phenomena. However, the desert Sahara has seen several in recent decades, the most recent in January 2022. the Sahara represents the hottest desert in the world and covers 11 countries from North Africa. This stretch of sand is bordered by The Atlantic Ocean to the west, the Red Sea to the east, the Mediterranean Sea to the north and the sahelian savannah South.
In reality, winter drafts bring cold, moist air from The Atlantic Ocean and the north of Mediterranean to the Sahara. In winter, the humid air of Atlantic oceans, Mediterranean and Indian reaches the region by tributaries north of the Saharawhile monsoon rains fall in summer south of the Sahara.
the Central Sahara therefore represents a very dry region, receiving less 100mm of rain per year, but overflowing with water on three of its ends. Therefore, the edges are wetter than the center. The snow tends to form there.
Some favorable conditions for snowfall
The training of the snow requires two different meteorological characteristics: cold temperatures and of humid air. The appearance of snow is the result of a combination of atmospheric currents and surface characteristics that result in falls of snow. In the Saharathe temperatures are generally high, exceeding the 50°Cbut can also be low due to dry surface and cloudless sky. clouds.
At high altitudes, as in mountains of the Atlas to Morocco and in Algeria, the rising air cools and condenses. Also, if the ground is cold, the snow may not melt fast enough and last. In these weather conditions and in the mountainous areasthe snow can then fall to Sahara.
The frequency of snowfall in the Sahara
The main characteristics of Sahara are its size (9 million square kilometers) and its distance. This state of affairs forces scientists to intervene to find out the frequency of snowfall in the deserts. To this end, they use techniques of satellite remote sensing to determine the timing, amount and distribution of precipitation and snowfall in the Sahara.
However, these phenomena only occurred during the last decades. Moreover, there was little evidence of the existence of models of snow until the satellite data become available in 1970s. It is therefore possible that the snow at Sahara has been more common in the past than previously thought. It would therefore be interesting to explore this possibility using anthropological data and of oral traditions.
SOURCE: THE CONVERSATION