first up, your colors are WAY too warm for the valley of death.
Redo the cliff colors in a more somber shade, like purple and blue or shades of either. Alternatively, use dark blue and bright red as light and shadow to create a more surreal effect.
Second, study up some different rock formations! You've done alright here, but it looks too much like a desert formation like the grand canyon than the more wobbly-lookin' ones you find near watery areas.
An example, in the form of a kinda silly inspiration poster that happened to show off what I mean well enough: