The Pacific Northwest is cut in half both physically and climatically by the looming Cascade Range, which runs like a rugged spine from Canada down to California. Thanks to this substantial geographic barrier, the region’s vegetation and terrain are extremely varied.
The area to the west of the Cascades receives an enormous amount of precipitation (up to 200in a year in the Hoh River Rainforest) and hence boasts numerous glaciers, record-breaking snowfalls and a lush temperaterain forest that shelters some of the world’s oldest and largest trees. Traveling inland, the lofty mountains – which culminate in 14, 411ft Mt Rainier – suck up much of this moisture from the atmosphere, leaving the areas to the east of the range languishing in arid steppe and semidesert (Pasco in southeast Washington gets less than 6in of rain a year).
Cocooned on a massive ice-age floodplain, the eastern parts of Oregon and Washington lie on the dry Columbia River plateau, a region characterized by its many coulees, canyons and gorges. Indeed, the spectacular Columbia River has the second-largest water volume in the US (after the Mississippi) and drains the whole region through a magnificent river gorge that provides the only natural break in the Cascade Mountains south of the Canadian border. The Columbia is also renowned for its numerous dams that provide vital hydroelectric power and have transformed a once-barren desert into a veritable Garden of Eden that produces fine wines, classic vegetables and more than half of the US apple crop.