Lewis-Clark Valley AVA

Lewis-Clark Valley AVA

46° 25' 00'' N


117° 3' 00'' W




about this subregion

Overview of the Lewis-Clark Valley AVA

The Lewis-Clark Valley AVA is a distinctive wine-growing area in the Pacific Northwest, spanning across southeastern Washington and into northwestern Idaho. It is unique as the only American Viticultural Area (AVA) in Washington that crosses into Idaho, making it a cross-border AVA. This region is renowned for its dynamic environment which significantly influences the viticulture here.

Climate and Soil

The climate of the Lewis-Clark Valley AVA is termed as the "banana belt" of the area due to its temperate conditions amidst colder surrounding regions. It features warm summers and mild winters, with an annual precipitation varying between 11 to 22 inches. The growing season is conducive for viticulture, providing 2600-3000 growing degree days, which allows for the successful ripening of a wide variety of grapes.

The soils in this AVA are predominantly loess and Mollisols. Loess is a wind-deposited silt that provides excellent drainage and moderate fertility, ideal for grape growing. Mollisols, derived from decomposed bunchgrass roots, are rich in organic matter and enhance moisture and nutrient retention, supporting robust vine growth.

Main Grape Varieties

The Lewis-Clark Valley AVA is home to several key grape varieties including Pinot Noir, Merlot, and Chardonnay. These varieties benefit immensely from the region's optimal growing conditions influenced by the unique climate and fertile soils, contributing to the production of high-quality wines that are gaining recognition in the wine industry.


vinerra illustration

Vineyard Hectares





Discover Terroir

Landscape of the Lewis-Clark Valley AVA

The Lewis-Clark Valley AVA is positioned at the confluence of the Snake and Clearwater rivers. This area spans across southeastern Washington and into northwestern Idaho, encapsulating parts of both states. The AVA is notably close to the cities of Lewiston, Idaho, and Clarkston, Washington, which lie adjacent to each other across the state border.

Landscape Features

The defining features of the Lewis-Clark Valley AVA are its steep canyons and rolling benchlands, which are a direct result of the ancient geological activities of the Snake and Clearwater rivers. The landscape is marked by these dramatic river canyons, which provide not only stunning scenic views but also contribute to the area's viticulture by creating varied microclimates within the region. These canyons help moderate the climate, making the area suitable for grape growing despite the broader region's range of temperatures.

Topographical Influence

The topography of the Lewis-Clark Valley AVA varies significantly from deep gorges to elevated plateaus. This variation in elevation and the protection offered by the canyon walls against the elements make the region particularly conducive to agriculture, including the cultivation of vineyards. The landscape's natural slopes ensure excellent drainage, while the river valleys trap warmth, which helps in extending the growing season.

The landscape of the Lewis-Clark Valley AVA not only defines its aesthetic appeal but also plays a crucial role in the cultivation of diverse grape varieties that thrive in this distinctive terroir.

Climate Overview of the Lewis-Clark Valley AVA

The Lewis-Clark Valley AVA enjoys a unique climate often described as the "banana belt" of the Pacific Northwest due to its relatively mild weather compared to the surrounding regions. This area benefits from a combination of warm summers and mild winters, which are ideal for viticulture.

Temperature and Growing Season

The region typically experiences a significant amount of growing degree days (GDD), ranging from 2600 to 3000 annually. This measure of heat accumulation during the growing season is crucial for the ripening of grapes and influences the types of varietals that can be successfully cultivated in the area.

Precipitation Patterns

Annual precipitation in the Lewis-Clark Valley AVA varies between 11 to 22 inches. This variability affects vineyard practices and grape characteristics. The distribution of rainfall throughout the year, with less during the critical harvest months, generally allows grapes to mature without the complications of excess moisture, reducing disease pressure on the vines.

Climatic Influences on Viticulture

The steep canyons and bench lands formed by the Snake and Clearwater rivers not only define the landscape but also play a critical role in moderating the local climate. These geographic features provide natural frost protection and help to maintain consistent temperatures across the vineyards. The good air drainage in the valleys further helps to protect the vines during colder spells, ensuring a stable environment for grape maturation.

The climate of the Lewis-Clark Valley AVA creates an advantageous environment for growing a variety of grape types, contributing to the production of diverse and high-quality wines.

Common Soils of the Lewis-Clark Valley AVA

The Lewis-Clark Valley AVA, a region acclaimed for its viticulture, is characterized by two predominant soil types that significantly influence the cultivation and quality of grapevines. These soils, shaped by the area's geological history and climatic conditions, provide a foundation for growing a variety of grape vines. Below, we explore the specific characteristics of these common soils:

  1. Loess: Loess is a wind-deposited, silt-based soil that covers much of the Lewis-Clark Valley AVA. This fine-grained, fertile soil is known for its excellent drainage and moderate fertility, making it highly suitable for viticulture. Loess retains just enough water to sustain vines during dry periods, yet drains sufficiently to prevent waterlogging, which can be detrimental to the roots. The mineral-rich nature of loess also contributes to the growth of grapes that can produce wines with a good balance of acidity and minerality.
  2. Mollisols: Mollisols in the Lewis-Clark Valley AVA are primarily derived from decomposed grass roots, which contribute to the soil's high organic matter content. These soils are among the world's most fertile and are particularly well-suited for agriculture, including grape growing. The high organic content ensures that the soil retains adequate moisture and nutrients, which are essential for the development of robust and healthy vines. Additionally, the structure of Mollisols facilitates good root penetration, allowing vines to establish a strong and deep root system, which is vital for long-term vine health and grape quality.

These soils not only support the diverse varietal portfolio of the Lewis-Clark Valley AVA but also enhance the unique terroir expression found in its wines, allowing vintners to produce distinctive and high-quality wines that reflect the essence of this unique viticultural area.


Most Common Grapes of the Lewis-Clark Valley AVA

The Lewis-Clark Valley AVA is distinguished by its unique geographical and climatic conditions that support a wide range of wine grapes. This region's ability to grow diverse grape types stems from its "banana belt" climate, providing a warmer and more temperate environment compared to surrounding areas.

Most Common Red Grapes

  1. Pinot Noir: Pinot Noir in the Lewis-Clark Valley thrives due to the region’s unique microclimate, which offers cooler zones ideal for this particular grape. Pinot Noir requires a balance of cool temperatures and adequate sunlight to develop its thin skin and ensure a proper ripening period. The valley's lower elevation vineyards benefit from the moderate temperatures, which help avoid the risk of spring frosts that can damage early buds.
  2. Merlot: Merlot is well-suited to the slightly warmer areas of the Lewis-Clark Valley AVA, where the climatic conditions prevent the grape from ripening too quickly. It needs a consistent growing season that avoids extremes in temperature to maintain the structured growth necessary for optimum vine health and berry development. The loamy soils and good drainage of the area support the vigorous growth of Merlot vines, making them less susceptible to water stress and common vine diseases.

Most Common White Grapes

Chardonnay: Chardonnay prospers in the Lewis-Clark Valley due to its ability to adapt to a variety of climatic conditions, although it particularly benefits from the region’s warm days and cool nights. These conditions allow Chardonnay to maintain its essential acidity while achieving full phenolic ripeness. The well-drained loess soils of the valley also contribute to the health of Chardonnay vines, encouraging deep rooting which is beneficial for stabilizing vine vigor and enhancing drought resistance.

Each of these grape varieties, coupled with other grapes like Cabernet Sauvignon, contributes to the rich tapestry of wines produced in the Lewis-Clark Valley AVA, supported by a unique interplay of climate, soil, and careful vineyard management practices that highlight the region's viticultural potential.

Most Common Wines from the Lewis-Clark Valley AVA

The Lewis-Clark Valley AVA, a distinguished wine region straddling the borders of Washington and Idaho, is celebrated for its unique microclimatic conditions that allows producers to craft distinctive wines.

Most Common Red Wines

  1. Pinot Noir: The Pinot Noir wines of the Lewis-Clark Valley are noted for their elegance and subtlety. They typically showcase aromas of red fruits like cherries, raspberries, and strawberries, often accompanied by an earthy undertone that reflects the terroir of the region. These wines are generally medium-bodied with a silky texture and a flavor profile that mirrors their aromatic complexity, offering a harmonious blend of fruit and earthy notes with a smooth finish.
  2. Merlot: Merlot from this AVA is appreciated for its robustness and depth. These wines often feature rich flavors of black cherry, plum, and blackberry, complemented by nuances of chocolate and sometimes a hint of spice. The warm days of the region contribute to the full ripening of the grapes, which imparts a lush fruitiness to the wines, while the cool evenings ensure that the wines retain their acidity and structure, making them both rich and balanced.

Most Common White Wines

Chardonnay: Chardonnay from the Lewis-Clark Valley AVA typically exhibits a complex array of flavors and aromas due to the region's unique growing conditions. These wines often feature a balance of fruit and minerality, with common notes of green apple, pear, and sometimes a hint of citrus. The cooler growing conditions in the valley also lend a crisp acidity that can be balanced with a creamy texture if the wine undergoes malolactic fermentation and oak aging, adding layers of vanilla and toasted almond to the profile.

These wines, as well as other styles like Cabernet Sauvignon, represent the diverse potential of the Lewis-Clark Valley AVA, each bringing its unique profile to bear in the glass.