Topography
A very important factor that accounts for the unique weather pattern of specific vineyards along the coast is topography. Parallel along the coast of California is a string of mountains formed by the sub-duction of the Pacific and Farallon Plates under the North American Plate. Not only were soils scraped and piled up to form mountain sides but inland seas were jutted into the air, volcanoes erupted, and rivers drained to the Ocean. This topography of the coast effects what happens to the cool air as unobstructed prevailing winds push the cool air inland. The coastal mountains perpendicular to the prevailing direction of air flow prevent the penetration of the low-level cool air mass: being heavier, it does not get pushed up and over vertical obstructions. So, even if you are right on the coast you may have temperatures warm enough to grow grapes if your vineyard juts above 1000 feet into the warmer top layers of air mass – remember, the higher the vineyard, the warmer the climate in this instance.
Interestingly, the cool bottom layer continues to move laterally up east-west breaks in ridges created by rivers and streams, as is the case in the Russian River (and the Wheatfield Fork of the Gualala River where we farm). As you might expect, there is a limit to the extent of cooling as you travel inland as the land mass will gradually warm the air in the summer. After traveling about 7-9 miles you begin to get far enough from the cold Pacific Ocean to experience warm days.
