The Sahara Desert looked more like the Rocky Mountains this weekend after it snowed there for the fourth time in nearly 40 years. The world's largest desert was blanketed in 16 inches of snow in the town of Ain Sefra in Algeria, also known as the "gateway to the desert."The Sahara is one of the driest and hottest places on earth, reaching extreme highs of 122 degrees. That makes enough moisture there for snowfall a rarity. But a high pressure system moving through Europe pushed cold air farther south than usual and into North Africa, which caused an unusual cold snap in the desert.While scientists can't attribute this individual weather event to climate change, extreme weather events will become more common in the future as the climate changes.