Driving I-90 over Snoqualmie Summit east of Seattle, for instance, you pass quickly from the lush green westside to a dry tan eastside, firs giving way to pines in a few miles. When you hit the flood basalt/sagebrush steppe down by the Columbia River at Vantage, Washington, you exclaim, “My God, this is a different world!”

You can experience the same rapid passage through great diversity in short distances on Canada 1 along the Fraser River running east from Vancouver, B.C. up and around to Lytton, one of the driest places in all of Canada. You can also experience the transition on I-80 east from Portland through the Columbia Gorge to Hood River and The Dalles and beyond.

Leeward & Windward Sides

Everyone who takes these routes is struck by dramatic changes in the landscape. And they leap (prematurely) to the common conclusion that the “westside” and “eastside” of these sub-regional divides represent radically different worlds. Therefore, they presume, Cascadia must only apply to the green, lush, moist, westside.

But this common conclusion misapprehends the nature of the rhythm of this land.  Keep going!  Find out what’s on the other side of the other side! If you keep going all the way over the Rocky Mountains in Montana down onto the High Plains, then you’ll discover what a truly different world looks like. In Cascadia “westsides and eastsides” go together, but when you run out of “west and eastsides,” then you know you’ve entered another world.

Now, in intercepting the moisture-laden rafts of clouds driven by the prevailing westerlies off the Pacific Ocean, our mountains create their own weather. They force cloud-banks up, cooling and compressing them with elevation, squeezing out moisture like a sponge. As the air masses rise over the ridgeline, and roll down the other side, pressure is released, the air warms and dries out, drying out the land and vegetation in the process. This well-known dynamic is called “orographic precipitation,” and is the cause of the “wet/dry side” phenomena.
             Wet and dry sides, westside and eastside, then, emerge as “windward and leeward” sides of the mountains. The “lee shore” is the sheltered side, the warmer, drier side, out of the full blast of the scouring wind. The drier the leeside, the steeper the mountains on the windward side.

Beware of self-contained pre-existing categories! For “The Eastside” does not stand alone by itself. Rather, it only emerges and has meaning as part of the pair--windward and leeward sides. Each is the other side of the other—they go together!

  Just as the same rain runs down both sides of the ridgeline, when you say “westside” or “eastside,” what you’re referring to is a unity differentiated into two halves--that is, “windward and leeward faces”--of the same mountains. You can’t have one without the other. Windward and leeward are not mutually exclusive opposites, but rather two faces of the same phenomena.

In addition, its important to note that the cool steppes and volcanic deserts on the leeward side of the Coastal Ranges (Trinity Alps & Klamath-Siskiyous to the south and B.C. Coast Range north into SE Alaska), as well as the leeward of the Cascade Range, are not true “latitudinal deserts” caused by climatic zones (e.g. as in Baja California), but rather “azonal” or mountain-caused “rain-shadows.” There’s a big difference. In true “zonal” deserts, everything is dry and mostly hot. By contrast, wet and dry sides are inherent to mountainous terrains.

Moreover, large regional rivers run through these steppes and volcanic deserts, rather unusual behavior for true latitudinal deserts.

What we see in Cascadia, then, is a succession of windward-and-leeward sides rising and falling in an alternating rhythm across the grain of the land.

When people keep repeating “westside vs. eastside,” (or insist on the importance of the so-called “Cascade Curtain,” as if that settled the matter), I reply, “which westside or eastside do you mean?” For there are at least four “westsides and eastsides” running from coast to crest. The quintessential Cascadian tree, Western Red Cedar, for instance, appears and reappears in a succession of windward westsides all the way to the Continental Divide in Montana and British Columbia.

No, the simple dichotomy of  “west vs. eastside” is incomplete and misleading, and needs, finally, to be set aside.

Continuity & Contrast Form a Matrix

What is most characteristic of Cascadia, then, is precisely this alternating rhythm of windward/leeward sides running across the grain of the land.

Hence, these two axes—north/south with the grain, and east/west against the grain—organize the lay of the land in Cascadia. Proceeding north and south we find remarkable continuity over long distances. Following the same “transect” along the coastline, for instance, you stay in much the same zone with only slight differences over many miles. Sitka Spruce, that lover of fog and salt-spray, shows up all the way from Cape Mendocino in northern California to Yakutat Bay in the corner of the Gulf of Alaska.

At the same time, traveling a transect from the Oregon Coast to Yellowstone Park, you encounter tremendous diversity within the densely packed landscapes running across the grain.

Continuity in one direction, and contrast in another—these two axes are key to the character of Cascadia. They form a lattice-work or matrix of life here.

In short, what makes a region a whole is not that “everything’s the same” (similarity or “internal homogeneity”), but rather the rhythm of the land and the characteristic regime of life it reveals. Its obvious that there’s clear continuity along the same axis running with the grain of the land, but the challenge in Cascadia is to discern the deeper integrities of the land in its characteristic rhythms running across the grain.

Without taking into account the intertwining of these double axes of continuity and contrast which constitute the matrix of this land, standard geographies seem to get lost. It seems highly dubious, for instance, to isolate the coastline as one long skinny strip strung out almost 2000 miles, and call it a “bioregion,” without relating it to the life of the land on either side which feeds it. How can Ecology ignore the flows and connections across the grain of the land? Such an approach privileges internal similarity, while ignoring the inherent diversity which forms the character of the region.

Because the complex grain of this land is deeply rooted in the “bones” of the earth, we need to recognize that such diversity is constitutive of the lay of the land of Cascadia.

To ignore the rhythm the land itself makes, would be like isolating the “Basin” from the “Range” in the great Basin and Range province bordering Cascadia on the south. But the fault-blocked Basin-and-Range go together as part of what John McPhee felicitously called the  “ondographic rhythm” inherent to that landscape.

Here, it’s the rhythmic layers which form the grain of the land. When you move across the grain, it’s the lamination of layers like waves cresting one upon another that you encounter. Each layer is not a different world, but rather part of a succession of waves breaking on the shore. The lamination which forms the grain of Cascadia is a kind of wave-train rolling in from the Pacific, just like the storm fronts rolling in overhead one after another, as part of the same system. It is not their isolation, but their inter-relation, that is significant.

Now, when to this characteristic rhythm we add in inherent differences in relief, slope, aspect, climate, soils, flora and fauna, to the diversity of landscapes, you begin to realize how densely packed this place truly is. Indeed, Cascadia is one of the most densely packed places in the world. Incredible diversity, fecundity, and density, burst forth from the lay of the land itself.

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