Sectioners at work canning grapefruit. About half of these girls are migrants. Winter Haven, Florida

The Dust Bowl exodus was the largest migration in American history that happened during the Great Depression. Although overall three out of four farmers stayed on their land, the mass exodus depleted the population drastically in certain areas. By 1940, 2.5 million people had moved out of the Plains states; of those, 200,000 moved to California. Arriving in California, the migrants were faced with a life almost as difficult as the one they had left. Like the Joad family in John Steinbeck’s “The Grapes of Wrath”, some 40 percent of migrant farmers wound up in the San Joaquin Valley, picking grapes and cotton. They took up the work of Mexican migrant workers, 120,000 of whom were repatriated during the 1930s.