Why does the Sierra Nevada have a rain-shadow effect on its eastern slopes?

The Sierra Nevada range creates a rain-shadow effect on its eastern slopes primarily due to its northwest-southeast orientation, which stands directly across the path of winter storm tracks moving from the Pacific Ocean.1

As these moisture-laden air masses encounter the mountains, they are forced to rise over the windward (western) slopes. This ascent causes the air to cool, leading to the release of copious precipitation on the western side of the range. By the time the air reaches the leeward (eastern) face, it has lost much of its moisture, resulting in significantly lower annual precipitation levels compared to the western foothills. This process is a classic example of a rain shadow, where the mountain barrier effectively blocks moisture from reaching the leeward side, contributing to the semiarid climate found in regions further east. The range's physical structure—an upfaulted, tilted block with an abrupt, steep eastern escarpment—further defines this sharp climatic contrast.123