The Columbia Valley AVA is an American Viticultural Area which lies in the Columbia River Plateau, through much of central and southern Washington State, with a small section crossing into the neighboring state of Oregon. The AVA includes the drainage basin of the Columbia River and its tributaries through much of Washington. Allen Shoup, president of Washington State's largest winery Chateau Ste. Michelle, understood the importance of obtaining appellation status for Washington State to grow the reputation of the vineyards. He hired Drs. Wade Wolfe and Walter Clore to petition the federal government for appellation status, a request that was granted in 1984. The Columbia Valley AVA is the largest wine region in the state of Washington, including over, of which over are planted in vineyards. The Columbia Valley AVA includes 99% of the total vineyard area planted in the state of Washington. Grapes grown here include Cabernet Sauvignon, Merlot, Chardonnay, Riesling, Syrah, Pinot gris, and Sauvignon blanc. Concord grapes and other Vitis labrusca grapes are grown in the region as well. The unique climates of the area allow the Columbia Valley to produce wines that are very fruit-forward, like California wine, but which also retain some of the balance and structure of European wine.
The vast size of the appellation allows for an array of diverse microclimates among the various sub-appellations, but the whole region shares the common climate traits of cold winters and long dry growing seasons with low humidity. The warm days and cool nights of the area help retain the balance of acid and sugar levels in the grape which give Washington wines their characteristic balance in flavors. The peak ripening of the grapes occurs during the last four to six weeks of the growing season, with the grapes hanging on the vines a little longer than in California. This allows the grape more time to develop maturity in tannins as well as other aroma and profile characteristics that will be brought out in the resulting wines. The longer growing season also allows the grapes to be harvested at a cooler temperature than in other more southerly wine regions. Deep winter freezes are the main climate threat to the grape growing industry of the Columbia Valley. Temperatures can drop from to less than in a matter of hours. Many vineyards incorporate wind turbines to keep air circulating around the grapes and stay warm enough to prevent frost. In most years, the vines enter into a long winter dormancy rather than freeze, which helps the vines come out of the winter and into the growing season healthier.
Irrigation
The rain shadow of the Cascade range leaves the Columbia valley with some areas receiving less than of annual rainfall. The development of intricate irrigation systems has allowed this area to become a premium grape growing region. Using water from the nearby Columbia, Snake, Yakima and Walla Walla rivers growers are able to precisely control the timing and amount of water that the vines receive. This control over the vines' potential vigor has a large influence on the resulting yields and quality of the grapes.