If you’ve ever listened to Woody Guthrie songs or looked at Dorothea Lange pictures, then you’ve heard about the Dust Bowl. What happened was, there was a period of unusually high rainfall over a great big area, and farmers moved in and plowed up the ground and planted wheat and cotton. Then the weather swung back to really dry and the wind came and literally blew those farms away. See, everybody had gotten so used to a mild and fertile climate that they thought of it as the norm. It wasn’t; they’d just been lucky for a generation or two.