The Pacific Northwest can be roughly divided into two strikingly different landscapes: wet and dry. Or call them green and brown. It’s damp and green to the west of the Cascades and relatively arid and brown to the east.
The PNW is famous for its rain, but what about the dry side? Why is there a desert over there?
It’s because of the rain shadow effect. Many dry places around the world exist because of this phenomenon. Here are the basics of how the rain shadow effect works in Washington and Oregon: