Chapter 29 of The Grapes of Wrath is an "inner" chapter and, therefore, short and lyrical in style. It is also a Biblical-styled chapter, as it depicts the Great Flood that is used as counterpoint to the Dust Bowl chapters earlier. Steinbeck makes use of pathetic fallacy (weather to depict emotional tone) as the apocalyptic weather is a kind of purgation--an excessive baptism that brings death across the land.
The chapter begins with much personification:
"...the gray clouds marched in from the ocean."
"...the wind...roared in the forests."
"the dry earth sucked the moisture down..."
"the steady rain whipped the shining water."
"the earth whispered under the beat of rain..."
Steinbeck's syntax is very much like that of Moses at the beginning of Genesis as he describes the Great Flood:
"I am going to bring floodwaters on the earth to destroy all life under the heavens, every creature that has the breath of life in it. Everything on earth will perish."
Steinbeck's style is plain, tough, and his tone is male and prophetic. Sentences are a mix of simple and compound, and his word choice is simple: he uses high frequency (everyday) words. He works in cause-effect mode, showing how nature affects humans. The torrential rain brings sickness and death. He names no one, only using "they," "people," "women," and "men." He uses dialogue but without quotation marks, which gives the chapter an eerie quality.
All in all, Steinbeck is setting us up for the climax, forshadowing the Joads fighing for survival during the flood. Also, his imagery foreshadows Rose 'a Sharon's breast-feeding the old man in chapter 30, as he focuses on "at last the mountains were full," "the dry earth sucked," "for two days the earth drank the rain." The second to the last sentence mentions "wrath," (title) but it does not give a source (either God or nature). Who is responsible for the wrath? Finally, the chapter ends with a gleam of hopeful symbolism:
Tiny points of grass came through the earth, and in a few days the hills were pale green with the beginning year.
Steinbeck shows how the extreme vegetative cycle is complete: from famine to flood, from death to life.