Location: South-central Washington
Designated: 2006
Total Size: 81,000 acres
Acreage Under Vine:
8,932 acres (3,615 hectares)
Top Varieties: Cabernet Sauvignon, Merlot, Chardonnay
Soils: Wind-blown sand 
Average Annual Precipitation: 6 inches

Two Things to Know:

  •  The Wahluke Slope is defined by a giant, ancestral alluvial fan. 
  •  It is one of the warmest appellations in the state, dominated by red varieties. 

Wahluke Slope is located in south-central Washington by the town of Mattawa. It is a sub-appellation of the Columbia Valley. The area is geographically isolated, bordered by the Columbia River, Saddle Mountains, and Hanford Reach National Monument. The name is a Native American term for ‘watering place.’ 

As one of the warmest regions in the state, the Wahluke Slope is known primarily for red grape varieties, particularly Cabernet Sauvignon, Merlot, and Syrah. Uniformities in aspect, soil type, and climate are the other major distinguishing features of the area. 

Map of Washington with the Wahluke Slope AVA in red, surrounded by the rest of the AVAs in muted greens and oranges.

The entire Wahluke Slope appellation sits on a large, ancestral alluvial fan, which has a constant, gentle grade of less than 8%. This makes the soils notably uniform over a large area. 

The topsoil is deep, wind-blown sand with a depth, on average, of more than 5 feet. This provides both ample drainage for vinifera vines and greater uniformity in plant vigor and ripening than seen in other areas of the Columbia Valley. 

The appellation’s slope and proximity to the Columbia River helps minimize the risk of frost, which can affect other areas. 

Elevations vary between 425 feet above sea level by the Columbia River, to 1,480 feet, though most vineyards lie below 1,000 feet. The appellation accounts for approximately 15% of Washington’s total acreage. 

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