Volcanic Origins
Long before the Ice Age floods, between 17 and 6 million years ago, the Columbia Plateau experienced some of the most voluminous volcanic eruptions in Earth's history. These weren't explosive volcanoes—they were fissure eruptions that oozed massive amounts of basaltic lava across the landscape.
Layers Upon Layers
The Columbia River Basalt Group consists of more than 300 individual lava flows stacked on top of each other. In some places, this basalt is more than 15,000 feet thick.
Why It Matters for Wine
Basalt weathers into mineral-rich soils that provide essential nutrients for grapevines. The fractured basalt also creates excellent drainage, preventing water from pooling around vine roots.
Many of Walla Walla's most celebrated vineyards are planted on or near exposed basalt, giving their wines distinctive mineral notes that sommeliers describe as "volcanic" or "stony."