What metaphors are used in Giants in the Earth by Ole Edvart Rolvaag?

Metaphor:

A gust of wind, sweeping across the plain, threw into life waves of yellow and blue and green.

Poverty-stricken, unspeakably forlorn, the caravan creaked along, advancing at a snail's pace, deeper and deeper into a bluish-green infinity--on and on, and always farther on. . . . It steered for Sunset Land!