Rain Shadow

weather · mountains · geography

Mountains block moisture. When wet wind hits a mountain, the air is forced upward and cools down. This makes rain fall on the windward side (the side facing the wind), leaving little water left for the other side.

The leeward side stays dry. The side of the mountain away from the wind is called the leeward side, and it gets much less rain. This happens because most of the moisture already fell as rain on the other side.

Deserts can form this way. Some of the world's driest deserts exist because of rain shadows created by tall mountains nearby. The Mojave Desert in California is one famous example.

It happens everywhere. Rain shadows occur on every continent wherever you have mountains and prevailing winds pushing air in the same direction. They shape where plants grow and how people live.