Snow and ice are unusual in desert regions but not completely unknown.
Temperatures in deserts can drop dramatically overnight but any snowfall is usually melted early the following day.
In cases like those seen this month in Algeria, high pressure systems of cold air have moved over land to the deserts, causing lower temperatures.
Such anticyclones tend to reach Saudi Arabia by moving clockwise out from Central Asia, picking up moisture en route which cools to form snow.
January 2022 and 2021 saw snow come to the Sahara and Saudi Arabia but it is not the first time these usually blisteringly hot spots have been blanketed in white.
In 2018, Ain Sefra was dusted in snow for the third time in 40 years.
The phenomenon has been noted in the town in 2021, 2018 and 2017, with the last recorded snowfall before that being in 1979.
Temperatures in the town usually range from 12C in January, the coldest month, to nearer to 40C in July.
While the Asir region of Saudi Arabia had its first snowfall in half a century last January, snow has hit elsewhere in the desert kingdom in recent years.
In 2020, temperatures dipped below freezing in the country’s mountainous northwestern regions including Tabuk, as a blizzard prompted officials to warn residents to keep warm.
A year earlier, snow fell in April.