The mountain range that creates a rain shadow in Washington is the Cascade Mountains.

The mountain range that creates a rain shadow in Washington is the Cascade Mountains.

• A. Cascade Mountains
• B. Sierra Nevada
• C. Rocky Mountains
• D. Appalachian Mountains

Answer: (A)

Understanding how mountains shape precipitation helps explain this. When moist air from the Pacific hits a mountain range, it is forced upward. As it rises, it cools and releases much of its moisture as rain on the windward (front) side. After crossing the peaks, the air descends on the leeward (far) side, warms, and becomes drier, creating a rain shadow—the drier area on the downstream side. The Cascade Mountains sit in Washington and block Pacific moisture, producing heavy rainfall on the western Washington slopes and a relatively dry, rain-shadowed eastern Washington. The other ranges listed don’t create Washington’s rain shadow in the same way: the Sierra Nevada is farther south and affects California and Nevada; the Rocky Mountains are farther to the west–east line but influence a different region; the Appalachians are in the eastern U.S. and don’t impact Washington's climate.

Understanding how mountains shape precipitation helps explain this. When moist air from the Pacific hits a mountain range, it is forced upward. As it rises, it cools and releases much of its moisture as rain on the windward (front) side. After crossing the peaks, the air descends on the leeward (far) side, warms, and becomes drier, creating a rain shadow—the drier area on the downstream side. The Cascade Mountains sit in Washington and block Pacific moisture, producing heavy rainfall on the western Washington slopes and a relatively dry, rain-shadowed eastern Washington. The other ranges listed don’t create Washington’s rain shadow in the same way: the Sierra Nevada is farther south and affects California and Nevada; the Rocky Mountains are farther to the west–east line but influence a different region; the Appalachians are in the eastern U.S. and don’t impact Washington's climate.