The nicknames commonly used in the 1930s for displaced farmers who lost their lands during the Dust Bowl droughts and storms are "Okies," Arkies," and "Texies," because most of them came from Oklahoma, Arkansas, and Texas.
They were forced to migrate to other parts of the state or the country in order to find work. They usually went west, primarily to California when it comes to Okies, where they often faced discrimination and poverty.
If you want to learn about the living conditions of Okies in this period, they are the main topic of John Steinbeck's The Grapes of Wrath, a very famous novel published in 1939.