Washington’s Wine Geography
Smart, sophisticated, and successful, Washington state’s wine industry is the largest and most commercially prosperous in the Pacific Northwest, and the second largest (by production and number of wineries) in North America.
The common image of Washington is of a state filled with snow-capped mountains, lush conifer forests, and lots and lots of rain. While not inaccurate, this image is incomplete. It is also a state with immense areas of desert-like scrub and high-elevation rolling hills.
From a viticultural standpoint there are two Washingtons: the marine-influenced third of the state west of the Cascade Range (mostly characterized by the Puget Sound AVA), and the continental-climate regions of south-central and eastern Washington (mostly within the Columbia Valley AVA). Each of these areas are important to Washington wine, but in very different ways.
Nintey-nine percent of Washington’s vineyards are planted in the arid ground of the Columbia River Basin, a viticulturally fecund region of continental climate-influenced weather deep within the rain shadow of the Cascade Range. Hot, dry, and sparsely populated, this part of Washington is a huge geography of dusty river valleys, undulating scrubland, desiccated rolling hills, and barren small mountain ranges. That such land can support grapes, as well as a wide variety of other agriculture, is thanks to irrigation, a fundamental requirement—and limiting factor—in the state’s wine success.
Key to Washington’s wine character is the abundant sunlight vines receive thanks to their northerly latitude. Eastern Washington receives about 17.4 hours of daily sunlight during the growing season—2 hours more than in California’s most important wine regions. Plus, the region’s clear skies—little cloud cover, no industrial air pollution, and lots of wind to remove particulates, mean the grapes receive a full measure of light intensity. The additional light acts as a substitute for extra hang time at the end of the season: Washington’s grapes can be harvested sooner, yet still achieve balanced ripeness and mature flavor.
The geology, topography, and climate of the Columbia Basin determines the character of Washington’s wines. Soils are varied in structure, but share a number of important characteristics. Most commonly, they are well-drained, friable loess (windblown silts) on top of basalt bedrock, so vine roots grow deep in search of moisture and vines tend to naturally put more energy into fruit ripening than vegetative growth. The soils are also generally alkaline in composition, which is thought to enhance fruit intensity, a trait often associated with Washington wines.
All of the Columbia Valley AVA is east of the Cascade Range, whose 10,000-14,000-ft. elevation is a significant rain barrier. While Seattle ion the western side can average 38-in. of annual precipitation, the heart of eastern Washington’s wine country averages between 7 and 12-in. annually, most of which falls in winter, outside of the growing season.
Since weather is reliably dry , winegrowers are rarely at the mercy of unpredictable or damaging weather events during the growing season, and the use of irrigation allows for extremely precise management of plant growth. An important benefit of the dryness (plus heat) is that it discourages pests and disease; there is little fungus and few bugs badgering the vines.
IDEAL FOR WARM CLIMATE VARIETIES
The weather is also reliably warm. In Prosser, in the heart of the Yakmia Valley AVA, summer maximum temperatures average between 88°F and 90°F. Annual Growing Degree Days vary from a low of around 2100 in parts of the Rattlesnake Hills to 3200 at other places within the Columbia Valley. This wide spectrum allows eastern Washington to successfully grow nearly all warm-climate vinifera varieties.
Also, the diurnal swing helps define the area’s wine styles. While daytime temps may average in the high 80s°F, nighttime temperatures in the Columbia Basin can easily drop to the 50s° or 40s°F. The desertlike warmth of the daytime helps develop full, ripe flavors in the grapes which are balanced by strong natural acidity retention due to the much cooler nights. Fresh fruit flavors and bright crisp acidity are hallmarks of Washington wine.
There is an important drawback drawback to winegrowing in the Columbia Valley: winter cold. Average winter minimum temperatures in the region of around 20°F to 25°F do not pose significant threats to grapevines, but not all winters are average. Roughly every 4 to 8 years the norm is shattered by arctic blasts that can bring sustained temperatures well below freezing, and sometimes as low as -20°F. Such temperatures can damage and even kill vines. It happened in 1996, 2004, somewhat in 2008 and 2009.
While none of Washington’s prime vineyards are located here, the Puget Sound area is nevertheless one of the driving forces behind the state’s wine success. How can this be?
The Puget Sound is home to the majority of Washington’s population and economic activity, as well as a significant proportion of the state’s most important wineries. With Seattle as its center, a dense welt of development swells around the city’s satellites of Everett, Bellevue, Tacoma, and Olympia. Here is the economic engine that drives the regional economy and demand for Washington wines. Seventeen miles east of Seattle, in the green vale of the Sammamish River Valley near the town of Woodinville, is a concentration of some of the most recognized wine names in the state. Here an exploding population of wineries has transformed this suburb into a locus of tasting rooms, and has become one of the most visited wine centers in the Northwest.
The emergence of Woodinville as a wine center is testament to the fact that while virtually all of Washington’s grapes are grown in the east half of the state, virtually all of the wines are purchased in the west half of the state. From the largest wine company in the Northwest (Ste. Michelle Wine Estates) to tiny boutique wineries producing less than a thousand cases, nearly 100 wineries either have headquarters or tasting rooms in Woodinville—and dozens more not actually in Woodinville still call Seattle and the surrounding area home.
Though there are vineyards and wineries scattered around the Olympic peninsula and San Juan Islands—a treat for adventurous wine tourists—their output is insignificant on a statewide scale. So while the Puget Sound AVA is not important from a grape growing standpoint, it is it is vital as a wine-selling venue and the key regional economic driver of Washington’s wine industry.