Rattlesnake Hills AVA (Sub-Appellation of Yakima Valley)

Rattlesnake Hills occupies the south-facing slopes of the Rattlesnake Hills, an east-west anticline of the Yakima Fold Belt, centered around the town of Zillah in south-central Washington. The appellation sits higher in elevation than the broader Yakima Valley, with vineyards established on ridges and terraces that benefit from good air drainage, reducing the risk of spring and fall frosts. The Cascade Range to the west creates a pronounced rain shadow, limiting annual rainfall to just 6 to 12 inches, while the Rattlesnake Hills ridgeline itself shields vineyards from freezing polar air. Higher-elevation sites within the AVA are above the reach of the ancient Missoula Floods, giving them a distinct soil character compared to much of the Columbia Valley.

• Elevations range from 850 to 3,085 feet, the highest point in the Yakima Valley AVA
• Arid continental climate with 6 to 12 inches of average annual rainfall; irrigation is required
• Ridgeline shelters vines from Canadian polar air, moderating winter freeze risk
• Higher vineyard sites sit above the historic Missoula Flood deposits, creating unique soil conditions

The distinguishing geological feature of Rattlesnake Hills is the Ellensburg Formation, which underlies approximately half the appellation. This sedimentary formation was created by erosion of rock from the Cascade volcanoes and produces the shallow, well-drained silt loam and loam soils that dominate the AVA. These nitrogen-deficient, low-vigor soils encourage vines to struggle, concentrating fruit quality. The presence of calcium carbonate, known locally as caliche, in some areas helps maintain acidity in the fruit late into the growing season. This geological profile is notably different from the basalt-dominated flood deposits that define much of the broader Columbia Valley.

• Approximately half the appellation underlain by Ellensburg Formation sedimentary rock
• Predominant soil types are silt loam and loam, shallow and well-drained
• Calcium carbonate (caliche) present in portions of the AVA, supporting late-season acidity retention
• Soils are low in vigor and nitrogen-deficient, naturally limiting yields and concentrating fruit

Rattlesnake Hills is almost evenly split between red and white wine grapes, with red varieties holding a slight edge. Riesling is the most widely planted variety, followed by Merlot and Cabernet Sauvignon. Syrah has also established a strong presence, with the region's elevation and continental climate producing wines with lifted acidity and well-defined structure. Malbec, Cabernet Franc, and a wide range of other varieties are grown across the AVA's 29 vineyards, which in total cultivate over 40 different grape varieties. Many Washington producers outside the region source fruit from Rattlesnake Hills vineyards for their own labeled wines.

• Riesling is the most planted variety, followed by Merlot and Cabernet Sauvignon
• Syrah, Malbec, and Cabernet Franc are increasingly important red varieties
• Over 40 grape varieties grown across the AVA's vineyards
• Many prominent Washington wineries outside the region source Rattlesnake Hills fruit

Bonair Winery, founded in 1985 by Gail and Shirley Puryear after their first vines were planted in 1980, is the AVA's most prominent estate and the driving force behind the original AVA petition. The Puryears also steward the Morrison Vineyard, the oldest in the AVA at planting in 1968. Hyatt Vineyards, established by Leland and Lynda Hyatt in 1983, has grown to nearly 200 acres across multiple sites and is one of the largest producers in the appellation. Portteus Vineyards, established in 1981, is recognized as a 100-percent estate-bottled producer. Two Mountain Winery and Horizon's Edge Winery are among the other notable Wine Trail members, while wineries including Owen Roe, Sheridan, Andrew Will, and Cote Bonneville source fruit from key AVA vineyards such as DuBrul, Elephant Mountain, and Dineen.

• Bonair Winery: founded 1985 by Gail and Shirley Puryear; estate vineyards include the 1968-planted Morrison Vineyard
• Hyatt Vineyards: established 1983; nearly 200 acres across multiple estate sites; Ellensburg Formation subsoils
• Portteus Vineyards: established 1981; 100% estate bottled; recognized by Wine Enthusiast as a great Cabernet producer
• DuBrul, Elephant Mountain, and Dineen are key AVA vineyard sources for prominent Washington producers

Rattlesnake Hills received official AVA status on March 20, 2006, becoming Washington State's ninth federally designated viticultural area. The petition was led by Gail Puryear of Bonair Winery, supported by 10 other vineyard and winery owners, and was approved by the TTB on the basis of distinguishing topography, climate, and soils. Under standard federal TTB rules governing all American Viticultural Areas, at least 85 percent of grapes used in a wine must originate within the AVA boundary for a producer to use it as the appellation of origin on the label. The appellation lies entirely within the Yakima Valley AVA, which is itself entirely within the Columbia Valley AVA.

• Established March 20, 2006 as Washington's ninth federally recognized AVA
• Petition led by Gail Puryear of Bonair Winery with 10 co-petitioners
• 85% fruit sourcing from within the AVA required to use the appellation name on a label
• Nested within both the Yakima Valley AVA and the larger Columbia Valley AVA

Commercial viticulture in Rattlesnake Hills dates to 1968, when the Morrison Vineyard was planted for Chateau Ste. Michelle with Riesling and Cabernet Sauvignon. Additional vineyards followed in the late 1970s and early 1980s, including the Hyatt Vineyard, Whisky Canyon, Outlook, and Portteus. The Rattlesnake Hills Wine Trail, centered in Zillah and accessible via exits 50, 52, and 54 along Interstate 82, includes 18 member wineries, most located on estate vineyards with views of Mount Adams and Mount Rainier. Tasting rooms along the trail are open to the public without reservations during posted hours, making it an accessible destination roughly two and a half hours from Seattle, Spokane, and Portland.

• Commercial viticulture dates to 1968 with the Morrison Vineyard planting for Chateau Ste. Michelle
• Hyatt, Portteus, Whisky Canyon, and Outlook vineyards established in the late 1970s and early 1980s
• Wine Trail has 18 member wineries centered around Zillah, accessible off I-82
• Most tasting rooms open without reservations; approximately 2.5 hours from Seattle