How does Momaday use adjectives and descriptive phrases to show profound respect for Rainy Mountain?
Great green and yellow grasshoppers are everywhere in the tall grass, popping up like corn to sting the flesh, and tortoises crawl about on the red earth, going nowhere in plenty of time. Loneliness is an aspect of the land. All things in the plain are isolated; there is no confusion of objects in the eye, but one hill or one tree or one man. To look upon that landscape in the early morning, with the sun at your back, is to lose the sense of proportion. Your imagination comes to life, and this, you think, is where Creation was begun. (The Way to Rainy Mountain, "Introduction," p. 5)
Momaday's adjectives and descriptions in the passage you cite simultaneously create images of specific, concrete details, as well as of a vast, open and isolated landscape. The adjectives are mixed with verbs, of course (to create concrete details) so I'll italicize the adjectives.
The "Great green and yellow grasshoppers" (visual imagery) pop up like corn to "sting the flesh" (tactile imagery), and they are "everywhere [adverb]." Turtles crawl on "red earth." These concrete details bring verisimilitude, or realism, to the scene being described, and create the localized, immediate view of the scene.
The view moves outward, then, to the vast landscape. When one scans the big picture, so to speak, "there is no confusion of objects in the eye," as only "one hill or one tree or one man" is seen. The plain is a lonely place.
The concrete details of the local view combine with the images of the overall view, to establish the setting that leads to the writer's conclusion, which demonstrates his profound respect for the plain, where, one might think, creation was begun.