How does Momaday use adjectives and descriptive phrases to show profound respect for Rainy Mountain? Great green and yellow grasshoppers are...

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.