Wahluke Slope AVA

Wahluke Slope is an American Viticultural Area (AVA) located within Grant County, Washington. It was established on January 6, 2006, by the Alcohol and Tobacco Tax and Trade Bureau (TTB), Treasury after reviewing the petition submitted by the Wahluke Slope Wine Grape Growers Association (WSWGGA), represented by Alan J. Busacca, Ph.D., proposing the establishment of the viticultural area named "Wahluke Slope."

Wahluke Slope is approximately 145 mi southeast of Seattle and immediately north of the Hanford Reservation of the United States Department of Energy (USDOE). "Wahluke" is a Native American word for "watering place," The appellation is within the vast Columbia Valley AVA and encompasses 80490 acre with approximately 8931 acre under vine which is nearly 15 percent of the state's total wine grape acreage. It is resident to more than 20 vineyards and at least three wine production facilities. The region cultivates Merlot, Syrah, Cabernet Sauvignon, Riesling, Chardonnay and Chenin Blanc, but is primarily known for its Merlot and Cabernet Sauvignon.

Geography and climate
Wahluke Slope viticultural area is located on the Wahluke Slope of Grant County, Washington. It extends from the Columbia River in the west, the Hanford Site boundary in the southwest, the north bank of the Columbia River on the south up to the Wahluke Slope Wildlife Refuge in the east, and along the 1480 ft elevation of the Saddle Mountains on the north. Wahluke Slope has one of the driest, warmest climates in the state, allowing nearly complete control of vine vigor and ripening through irrigation.

The entire 81000 acre appellation sits on a large alluvial fan, making the soils notably uniform over a large area. The topsoil is deep, wind-blown sand with a depth, on average, of more than 5 ft. This provides both ample drainage for vinifera vines and greater uniformity in plant vigor and ripening than seen in other areas of Washington. The major distinguishing feature of the Wahluke Slope is its uniformity in aspect, soil type, and climate. The entire appellation lies on a broad, south-facing slope with a constant, gentle grade of less than 8%. This, along with the proximity to the Columbia River, helps minimize the risk of frost, which can affect other areas of the state.

The highest temperature ever measured in Washington state, as of 2021, was recorded at Wahluke on July 24, 1928, at 118 °F. This record was later tied at Ice Harbor Dam in 1961. The temperature was eventually surpassed on June 29, 2021, when Hanford reached 120 °F.

The area is largely within the Mattawa, Washington 99349 area code.