The Sahara Desert sometimes gets covered in thick, white snow.

Snow in the Sahara sounds impossible, but it has happened several times. The first time anyone recorded it was on January 18, 1979, in a part of Algeria called Ghardaïa. Since then, it has happened more often, with big snowstorms hitting in 2016, 2017, and 2018.Most of these snowy surprises happen near a town called Ain Sefra. This town is known as the Gateway to the Desert and sits about 1,000 meters (3,280 feet) above sea level. In 2018, the snow was so heavy that it reached 40 centimeters (15 inches) deep in some spots.This happens when a high-pressure weather system over Europe pushes freezing air down into North Africa. For snow to form, the desert temperature must drop below 0°C (32°F). Usually, the Sahara is too dry for snow, but sometimes storms from the Mediterranean Sea bring enough water to make it happen.When the snow lands, it creates a beautiful sight. You can see bright white layers sitting on top of sand dunes that are 180 meters (nearly 600 feet) tall. It usually melts quickly once the sun comes up, but for a few hours, the world's hottest desert looks like a winter wonderland.