How does Marian Calabro use imagery in The Perilous Journey of the Donner Party?

Imagery:

"Some of the hills were so steep that the wagons threatened to somersault. Then the Donner Party would lock the wagon wheels, slide straight downhill, and pray. Other times they would have to yoke all the oxen to one wagon, pull it uphill, and return for the next; or they used chains and pulleys to winch themselves upward. Some of the land was so rocky that the clatter of their wheels resounded for miles."

"Soon the group was plagued by clouds of alkaline dust, raised by its own motion, which made it hard to see ten feet ahead. Worse, alkali is caustic; the fine powder settles into the skin and burns it. The travelers began to feel as if they had rolled in fire."