In most deserts, mountains enhance rainfall and produce moist vegetated islands in the larger arid landscape. Here is an example from the northern Chihuahuan and Sonoran Deserts.

The location of forests in New Mexico and Arizona is largely a matter of the force and direction of the prevailing winds. These tend to draw along the chutes prepared for them by the cumbres of the Continental Divide. From the gulfs of California and Mexico, great wind rivers go over with enormous freightage of sunlit cloud. Surcharged, they pile and topple and carom against the raking ranges and give down the precious ballast of the rain. Or the wind leaves them in fleets, like great barges becalmed in mid-air, until they darkle and run together and reveal the true nature of clouds. On the miraculous floor of the air the rain stands upright between the mountains. In pure, shadowed grayness it stretches from cumbre to cumbre.

I dabbed the surface of this tiny pool with a finger … because I remembered the Tohono O'odham people. …, and how it is their customary belief that water is not to be taken boastfully … To ask for too much water is to invite disaster. Only in a place like this would you bow your head and humbly request just the water you need and no more. Only here would you walk away from water when thirsty, but not thirsty enough.