Has anyone ever told you that in order to visit one of the truly exotic and varied wine-growing regions in the world you don't have to travel to places like Argentina or Spain (although those destinations would be great fun!)? Instead, go no further from Portland or Seattle than your backyard and spend a day, or several, exploring the Columbia River Gorge.

Many people know about and have spent time in the Columbia River Gorge National Scenic Area that extends from Troutdale on the west to Maryhill Museum on the east, truly one of the natural wonders of the world. But did you know that the Columbia Gorge is also part of two American Viticultural Areas (AVAs or appellations), the areas of which lie within and adjacent to the national scenic area? These are the Columbia Gorge AVA and the Columbia Valley AVA. Winegrowers here capture the essence of wine touring along the Columbia Gorge when they say “A World of Wine in 40 Miles” because you can taste refreshing floral Gewurztraminer, gorgeous balanced Pinot Noir, big and juicy Zinfandel, bold bright Cabernet Sauvignon, and many more wines, all made from Gorge-grown grapes. How is that possible? Read on! To understand the wonderful and unique character of the Columbia Gorge for growing wine grapes, we need a special word. That word is terroir (pronounced tair-wahr), a French word that describes the complex interplay among climate, soils, geology, and vineyard characteristics such as slope and aspect that influences the character and quality of wine grapes. Terroir recognizes the special characteristics of a vineyard or a region that give wine its individuality. Well, to mix a metaphor, the Columbia Gorge wine region has terroir (or, as we will see, terroirs) coming out its proverbial ears. The Columbia Gorge has been famous for more than a century for its fine pears, apples, cherries and other fruit, but except for a few small plantings of wine grapes in the late 1800s and early 1900s, the Gorge remained unexplored terrain for wine grapes until the early 1970s. It did not take long before the wonderful potential of the Gorge was recognized though. Today, the Columbia Gorge area is home to about 50 vineyards and more than 30 wineries. The Columbia Gorge AVA was established in 2004 and is one of the newer AVAs in the Northwest, whereas its big brother, the massive Columbia Valley AVA at over 11 million acres, was established in 1983. The Columbia Gorge AVA is small enough at about 185,000 acres to fit inside just the central part of the National Scenic Area. In contrast, the Columbia Valley AVA is so large that just its southwest tip juts into the Gorge. One great thing about wine touring in the Columbia Gorge is that the Columbia Gorge Winegrowers Association www. columbiagorgewine.com can provide maps, tips, and information to guide you to vineyards and wineries, regardless of which AVA you may be in. Some of the same characteristics that lend unique and wonderful qualities to the scenic area lend those same qualities to the terroirs of the AVAs: breathtaking cliffs and canyons, a climate that takes you from dense fir forest to sage-covered semi desert, amazing geologic features and more. The Geology Where to begin? Let’s start with the amazing geology that is exposed in the Gorge. The Columbia River has the largest flow of any river in North America that empties into the Pacific Ocean. Lewis and Clark saw millions of salmon and other migrating fish on their voyage of discovery in the early 1800s. The Gorge is more than 4,000 feet deep in places and the river bottom from The Dalles to the Pacific Ocean is at or below sea level. The geology of the Gorge ranges from ancient lava flows and volcanic sediments as old as 17 million years, to deposits from giant glacial outburst floods, to recent landslides and sand dunes. The Columbia River Basalts are the most dramatic and widespread rocks in the Gorge. They are the layered black lava flows that show cliffs with distinctive and characteristic columnar joints, sometimes more than 100 feet high. More than 300 individual lava flows were erupted from fractures in eastern Washington and northern Idaho between 17 million and 6 million years ago during the Miocene Epoch. Even in that distant time, the ancestral Columbia River flowed through the Cascade Range (though it was not as tall at that time) and many of these flows followed the course of the river all the way to the Pacific Ocean. Look for stacks of lava flows at scenic stops like Multnomah Falls or along the walls of the Gorge where the trees thin out between The Dalles and Maryhill Museum while driving either Washington State Highway 14 or Oregon Interstate 84. Other volcanic rocks from volcanoes large and small, young and old occur in places along the Columbia Gorge. For example, Underwood Mountain across the river from Hood River, Oregon, is home to some of the truly revered vineyards in the Northwest, and is part of an extinct volcano that erupted between about 850,000 years and 20,000 years ago. The high ridges to the south and west of The Dalles are made up of volcanic mudflows, consolidated volcanic ash, sediments, and lava flows from an extinct, long-forgotten volcanic center roughly in the vicinity of today’s Mount Hood that was active in the late Miocene and early Pliocene epochs between about 10 million years and 5 million years ago. But the Columbia Gorge as we see it today was really shaped by the Ice Ages, most recently about 20,000 years to 14,000 years ago, just the blink of an eye to geologists. Glacier ice did not shape the Gorge, however, although alpine glaciers on the flanks of Mount Hood and Mount Adams did push down into river valleys close to the Columbia. Instead it was the work of gigantic glacial floods that swept across northern Idaho, through the Spokane Valley, southwestward across eastern Washington, and down the Columbia River Gorge en route to the Pacific Ocean. These floods, from a huge glacier-blocked lake in western Montana called glacial Lake Missoula, are the largest known flows of water on Earth in the last two million years: the flow of water during the largest of the many floods was ten times the combined flow of all the rivers of the world! The floods, and there may have been several dozen outbursts from the lake over about 6,000 years, crested at elevations up as high as about 1,200 feet in places along the Gorge walls where the canyon narrows and water surged to great heights. One such place is on the exposed-rock uplands just downstream of The Dalles and the Columbia Gorge Discovery Center. The floods deposited all types of sediment from immense gravel bars (now partly covered by recent sand dunes) such as in the main channel of the Columbia River at the mouth of the Deschutes River between The Dalles and Maryhill Museum, to fine, silty sediments many tens of feet thick in side valleys where the floodwaters slowed. In fact, in places like the Deschutes River, floodwaters raced many miles upstream on this and other tributary rivers before dissipatingtheir energy and draining back to the Columbia. But perhaps the greatest visual drama created by the floods tearing through the Gorge is that of the areas of scabland, which consist of the rough and broken, eroded remnants of the basalt flows where the floods ripped part way through a lava flow, leaving stacks and spires of rock like at Beacon Rock State Park a few miles downstream from Bonneville Dam, and creating near moonscapes of rock like the flat scablands around Dallesport, Washington, across the river from The Dalles. And lest we forget, the floods eroded so much rock out of the main river channel over the eons that it left many side streams ‘hanging’ up to hundreds of feet above the river, creating the hundreds of waterfalls and cascades along the cliffs of the Gorge. Climate and Vegetation Rainfall in the Columbia Gorge area is concentrated in the winter, as in most parts of the Northwest, leaving summers sunny and generally cloud free. This creates an ideal climate for growing wine grapes, tree fruits, and dry land wheat, but that’s not the main story here, it’s the rainfall pattern along the Gorge. Most storms that deluge the Gorge originate over the Pacific Ocean and move easterly across the Cascade Range. As the storm clouds are forced to rise from sea level in the Portland area to pass over the Cascades, water is wrung out of them, making the western or windward side of the mountains very wet. But the same forces work in reverse as the storm clouds descend on the eastern or leeward side, creating a pattern of diminishing rainfall totals in the rain shadow to the east of the crest. Drive from Portland to Maryhill Museum for the first time and you will be witnessing one of the sharpest rainfall gradients anywhere in the world, more than one inch per mile, from 50 inches per year on the west side of the Hood River Valley and Underwood Mountain on the Washington side, east to less than 10 inches at Maryhill! Differences in the amount of sunshine versus cloud cover along this path, as well as differences in relative humidity of the air and other factors, lead to big differences in average annual temperature from Hood River to Maryhill and beyond, and especially in average summer growing season temperature. Although European or vinifera wine grapes are very hardy and can grow under an amazingly wide range of conditions, different grape varieties reach their highest potential quality under different optimal combinations of rainfall and temperature, soils, and so on. So it begins to be apparent how and why industrious Gorge winegrowers are utilizing the many terroirs that are literally just being discovered, to create a world of wine in 40 miles! The sharp rainfall and temperature gradients of the Columbia Gorge contribute to the wonderful changes in native plant life, from dense forests of conifers, mainly Douglas fir, of the western Gorge, to more open forests of Ponderosa pine and Oregon white Oak in the central part, to bunchgrass prairie, and finally to sagebrush covered semi desert out east. And we can’t forget the dramatic impact of slope direction on plant life, such as between Hood River and The Dalles where the moist north-facing slopes of the Oregon side are forest covered, whereas the dry south-facing slopes have oak-pine patches and grasses. One of the pure joys of wine touring the Columbia Gorge in the springtime is to bring a picnic and a wildflower book and to marvel at the diversity of different flowering plants along your route. The Climate for Wine Grapes Grape growers use a simple index of growing season temperature called ‘Growing-Degree Days’ or ‘Heat Units’ as a first indication of the potential of a place to grow grapes and also to consider which grape varieties (Chardonnay, Merlot, etc.) to plant. It is calculated and added up for each day between April 1st and October 31st each year, and of course it varies from year to year in each vineyard. Around the world, grape growers know that the optimal heat units for wine grapes range from about 2,000 on the cool end to about 3,500 on the warm or hot end. As great good fortune would have it, heat units in the Gorge range from about 2,000 on Underwood Mountain to about 3,400 at Maryhill. The talented and aware Gorge grape growers have been matching grape varieties with rainfall zones and heat units for about 35 years now, planting cool-climate varieties like Riesling and Gewurztraminer on Underwood, Pinot Noir in the slightly warmer Hood River Valley, Merlot, Syrah, and Zinfandel around The Dalles, and heat loving varieties like Cabernet Sauvignon, Cabernet franc, and Petite Verdot on the eastern end of the Gorge. Many other varieties are also planted in each of these places as growers experiment to find just the right match of site and variety for fine wine. Now we know the truth of the statement ‘A World of Wine in Forty Miles!’ In fact, because of the amazing range of grape climates in the Gorge, today, growers have planted more than 25 different varieties of wine grapes. The Final Elements As we wind this tale of terroirs in our backyard to a close, it would be an oversight not to weave in the final elements of great terroirs for wine grapes: geology, the resulting soils, elevation, and great landscapes. Wine grapes thrive in well-drained soils on sites that are up off of valley floors where sunshine, warm air and winds can bathe them and cold air, frosts, and water can fall away. As you tour the vineyards of the Columbia Gorge, notice how many of them are on steep slopes or on the many natural ‘benches’ in the landscape that were created by the Missoula floods peeling back layers of the Columbia River basalts. Given the complex geology of the Gorge, it’s no wonder that the soils range from those derived from hard basalts, to volcanic ash and pumice and mudflows, to those derived from ground-up granites in the Canadian Rockies by way of glaciers, the giant floods and wind, to those derived from local glacial and river sediments. Pick a soil texture from clay loam to bouldery sand and any mineral composition and you can find it in the Gorge. Elevation of vineyards ranges from near river level to almost 1,600 feet and they can be found facing all points of the compass, although south facing into the summer sun is most common. Of course, little of this terroir hokum pokum would matter without people. The final piece of the terroir puzzle is what we do with a favorite hillside; that is, someone with passion and vision and skill is needed to match a grape variety, the planting scheme, how they train and trellis the vines, what crop load to carry, and the tending of the vines throughout the season to make a vineyard sing with the possibilities of growing fine wine grapes. Think of the infinite possibilities of wonderful vineyard sites in the Columbia Gorge as a vast, multi-dimensional matrix of rainfall, temperature, elevation, slope, aspect, and soils; tour the Columbia Gorge wine country with eyes and senses open. You will find wonderful wines, passionate and dedicated grape growers and wine makers, incredible scenery, and you can prove to yourself that the Columbia Gorge really is ‘A World of Wine in Forty Miles.’

Dr. Alan Busacca, emeritus professor, Washington State University, taught soil science, agriculture and geology for 25 years. Today he operates Vinitas Vineyard Consultants; is codeveloping a Gorge vineyard, and is launching a new wine label, AlmaTerra, featuring single-vineyard Washington State Syrah and Viognier wines.

Alan can be contacted at This e-mail address is being protected from spambots. You need JavaScript enabled to view it or at This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Map prepared by Dr. Richard Rupp, Palouse Geospatial