Laying between the Beezley Hills to the North and the Frenchman Hills to the south , the growing region was severely impacted by the immense water flows of the Missoula floods . The scouring effect of the waters stripped the top soils down to the basalt and scoured out canyons referred to locally as " coulees " which are prominent features near many of the planted vineyards . The Columbia River forms the western border of the grape growing region
Missoula floods
Missoula Floods
Ancient Lakes of the Columbia Valley AVA