Joad took a few steps, and the flourlike dust spurted up in front of his new yellow shoes, and the yellowness was disappearing under gray dust.

– John Steinbeck

The Grapes of Wrath, Chapter 4. Gray is the color that symbolizes hopelessness in The Grapes of Wrath. Here gray dust covers Tom’s new yellow shoes, with yellow and gold being the colors of hope and prosperity in the novel. The slipping away of hope for people like Tom of being able to begin new and normal lives in the face of the Dust Bowl disaster is foreshadowed here.