Understand
The Sierra Nevada mountain range, like most ranges in the lower-48 states, runs north to south. Approaching the Sierra Nevada from the west is a very gradual process of small hills leading to larger hills, leading to small mountains, and so on. The east is a sheer cliff in comparison. At 4000 feet of elevation near Lone Pine, one can look straight up to the 14,505 ft 4,421 m snow-capped top of Mount Whitney, the highest peak in the United States outside Alaska.
This extreme change in elevation explains why there are no roads across the Sierra between Kernville and Mono Lake. In winter all but one of the passes are closed, and there are no crossings between Kernville and Lake Tahoe.
The Eastern Sierra receives very little rainfall because it lies in the rain shadow of the Sierra Nevada. Since weather systems generally approach the Eastern Sierra from the west or southwest, they dump most of their moisture onto the western flanks of the Sierra Nevada, leaving only a small amount for the Eastern Sierra.
The Eastern Sierra is part of the Great Basin. Water that falls in the Great Basin does not flow naturally into an ocean. Instead, water flows into various inland lakes such as Mono Lake and Walker Lake.
Large amounts of water are captured at the surface or pumped from the ground, and diverted to Los Angeles.
