Vineyards: 8,932 acres (3,615 hectares)
Top Varieties: Cabernet Sauvignon, Merlot, Chardonnay
Average Annual Precipitation: 6 inches
The entire Wahluke Slope appellation sits on a large alluvial fan, which has a constant, gentle grade of less than 8%. This makes the soils notably uniform over a large area. The uniformities in aspect, soil type, and climate are the major distinguishing features of the area.
Elevations vary between 425 feet above sea level by the Columbia River, which forms the western boundary, to 1,480 feet, though most vineyards lie below 1,000 feet. Precipitation averages less than 6 inches (15cm) annually. Irrigation is therefore required to grow vinifera grapes, as is the case in most of eastern Washington. Winds in the area lead to smaller leaf size and smaller grape clusters compared to other regions, concentrating the resulting wines.
The topsoil is deep, wind-blown sand with a depth, on average, of more than 5 feet (150cm). This provides both ample drainage for vinifera vines and greater uniformity in plant vigor and ripening than seen in other areas of Washington.
The appellation’s slope and proximity to the Columbia River, which forms its western boundary, helps minimize the risk of frost, which can affect other areas of the state. The area is geographically isolated, bordered by the Columbia River, Saddle Mountains, and Hanford Reach National Monument.
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. The appellation is a sub-appellation of the larger Columbia Valley.