Rattlesnake Hills AVA

Rattlesnake Hills AVA covers the south-facing slopes of the Rattlesnake Hills ridge, a roughly east-west oriented anticline in the Columbia River Basalt Group bedrock that rises 200 to 400 metres above the surrounding Yakima Valley floor. The ridge crest forms the northern boundary of the AVA; the Yakima River forms the southern boundary. The AVA's south-facing slope orientation across nearly all of its acreage produces consistent solar exposure and ripening conditions; the slope angle is generally moderate (5 to 15 degrees southward) with steeper sites on the upper slope and benches. Elevations range from approximately 250 metres at the Yakima River to 600 metres at the ridge crest. The slightly higher elevation than the broader Yakima Valley floor (the broader valley's lowest sites sit at approximately 150-200 metres) produces meaningful diurnal cooling: cold air drainage from the ridge crest and the elevation-based temperature difference contribute to cooler overnight temperatures relative to the broader valley floor. The combination of south-facing aspect plus slightly cooler nights produces growing conditions that balance ripening exposure with acidity preservation.

• South-facing slopes of Rattlesnake Hills ridge (east-west oriented anticline in CRBG bedrock); ridge crest northern boundary, Yakima River southern boundary
• Slope angle generally moderate (5-15 degrees southward); steeper sites on upper slope and benches
• Elevation 250-600 metres; slightly higher than broader Yakima Valley floor (150-200 m at lowest sites); produces meaningful diurnal cooling via elevation difference
• Climate balance: south-facing aspect provides ripening exposure; slightly cooler nights preserve acidity through the long growing season

Rattlesnake Hills' geological foundation is the Columbia River Basalt Group, with Wanapum Basalt (~15.6-15 mya) the dominant exposed formation across the AVA's slopes. Basalt outcrops and exposures appear at the ridge crest and upper slope; the basalt has been folded by the Yakima Fold Belt tectonic system into the south-facing slope orientation. Overlying the basalt at lower-slope sites are Missoula Flood deposits: gravels and sands at intermediate-flow zones, slack-water silts where backflow accumulated, all deposited during the cataclysmic flood sequence approximately 15,000 to 13,000 years ago. Windblown loess (Palouse-fringe aeolian silt) caps the upper-slope sites above the flood-deposit zone, particularly at the ridge crest and the upper benches. The combined soil profile is well-drained with significant variation by elevation: lower-slope sites carry deeper Missoula Flood gravels and silts, mid-slope sites carry mixed gravel and loess deposits, and upper-slope sites carry primarily loess over basalt at depth. The soil-stylistic mapping within the AVA produces variation in wine register: lower-slope wines tend toward structured red-fruit and tannic profile; upper-slope wines tend toward more elegant floral and aromatic register.

• Geological foundation: Columbia River Basalt Group bedrock (Wanapum Basalt ~15.6-15 mya dominant); folded by Yakima Fold Belt tectonic system into south-facing slope orientation
• Overlying deposits: Missoula Flood gravels + sands + slack-water silts at lower-slope sites; windblown loess (Palouse-fringe aeolian silt) caps upper-slope sites above flood-deposit zone
• Soil profile by elevation: lower-slope deeper Missoula Flood gravels and silts; mid-slope mixed gravel and loess; upper-slope primarily loess over basalt at depth
• Soil-stylistic mapping: lower-slope wines structured red-fruit + tannic profile; upper-slope wines more elegant floral + aromatic register

DuBrul Vineyard is Rattlesnake Hills' most-cited premium grower site and one of Washington State's most-cited grower vineyards broadly. Planted by Hugh Shiels (a retired physician) and his wife Kathy Shiels starting in 1992, DuBrul covers approximately 50 acres at elevations of 300-450 metres on the AVA's central slope. The vineyard plantings include Riesling (the vineyard's flagship variety, supplying Owen Roe's premium Riesling bottlings and serving as a critical reference for Washington Riesling), Cabernet Sauvignon, Merlot, Cabernet Franc, Syrah, and Chardonnay; the vineyard's structured, balanced fruit profile has attracted long-running supply relationships with many of Washington's top producers. Owen Roe, Avennia, Andrew Will, Gramercy Cellars, Long Shadows, and dozens of others have produced DuBrul Vineyard-designated bottlings. Hugh Shiels and Kathy Shiels also founded Côte Bonneville (the DuBrul estate winery, located within the AVA) to produce their own estate bottlings from DuBrul fruit; Côte Bonneville's flagship bottlings include the DuBrul Vineyard Reserve and a series of single-varietal expressions. The DuBrul Vineyard's prominence has made Rattlesnake Hills one of the most-cited Washington AVAs despite the AVA's overall modest production scale.

• DuBrul Vineyard: Rattlesnake Hills' most-cited grower; planted by Hugh + Kathy Shiels from 1992; ~50 acres at 300-450 m elevation on central slope
• Plantings: Riesling (flagship variety, Owen Roe premium bottlings + critical WA Riesling reference), Cabernet Sauvignon, Merlot, Cabernet Franc, Syrah, Chardonnay
• Long-running supply relationships: Owen Roe, Avennia, Andrew Will, Gramercy Cellars, Long Shadows, dozens of top WA producers produce DuBrul Vineyard-designated bottlings
• Côte Bonneville: Shiels family's DuBrul estate winery; flagship DuBrul Vineyard Reserve + single-varietal expressions from DuBrul fruit

Rattlesnake Hills' producer landscape is anchored by the premium grower-supplier sites (DuBrul Vineyard, Olsen Estates Vineyard, Hyatt Vineyards) plus a handful of estate wineries operating within the AVA. Olsen Estates Vineyard supplies premium fruit to numerous Washington producers and the Olsen family operates a tasting room and small direct-production operation. Hyatt Vineyards (founded 1983, one of the AVA's older operations) anchors a long-running family business producing accessible varietal wines. Two Mountain Winery (Patrick and Matthew Rawn, founded 2000) is the AVA's principal direct producer of estate-bottled wine, with significant vineyard plantings and a tasting room. Bonair Winery, Cultura Wine, Sheridan Vineyard, and smaller operations round out the direct-producer landscape. Côte Bonneville (the Shiels family DuBrul estate operation) anchors the upper-quality estate production tier. The AVA's overall production scale is modest compared to broader Yakima Valley sub-AVAs, but the premium grower-supplier role and the small-but-quality-focused estate producer community give Rattlesnake Hills a distinctive position within the Washington wine landscape. Tourism is moderate, anchored by the Rattlesnake Hills Wine Trail and the Yakima Valley tourism corridor.

• Direct producer anchors: Côte Bonneville (Shiels family DuBrul estate), Two Mountain Winery (Patrick + Matthew Rawn, founded 2000), Hyatt Vineyards (founded 1983), Bonair Winery, Cultura Wine, Sheridan Vineyard
• Premium grower-suppliers: DuBrul Vineyard (Shiels family), Olsen Estates Vineyard, Hyatt Vineyards; supply premium fruit to numerous Washington producers
• Olsen Estates: family-operated grower-supplier; tasting room and small direct-production operation
• Tourism: Rattlesnake Hills Wine Trail anchor; moderate tourism volume; part of broader Yakima Valley tourism corridor