The Lake Effect
The elevation of the surrounding mountains and the cooling effects of Clear Lake create a natural and perpetual “wind machine” in Lake County vineyards. Afternoon winds off the Lake cool the grapes during the heat of the day. During the summer months, daily temperature swings as much as 50 degrees are not uncommon. This intense cooling effect produces winegrapes with good acidity, improved tannic structure, darker color, and more concentrated fruit character. Wines made with this fruit is characterized by purity of fruit, high natural acidity, and restrained alcohol with phenolic ripeness.
Dig Deeper: Winds Create the Lake Effect
Lake County’s inland location and protection by mountain ranges result in local meteorological effects playing a more important role in creating Lake County’s micro-climates and account for the differences between various areas than in other coastal regions. Winds develop as the result of temperature differentials. Temperature gradients due to differences in elevation generate mountain-valley winds and water –land temperature differentials generate lake-land winds in accordance with the principles described below. Lake County is affected by Clear Lake as well as the surrounding mountains with winds that are driven by temperature contrasts. The phenomenon that water warms more slowly than adjacent land during the day and also holds its heat longer at night is the driving force that creates land-water winds.
At night, air passing over Clear Lake is warmed, becomes less dense and rises, while air over the relatively cool land on the shores becomes denser and sinks. This causes nocturnal katabolic winds to develop towards the lake. During the day the land becomes warmer than the lake, reversing the process and causing the winds to blow inland. The on-shore (anabatic) daytime winds are weaker than the off shore nocturnal winds. In many locations mountain valley breezes and land water breezes result in incomplete circulation. Warmer air that is displaced by the cooler breeze rises, disperses broadly, and mixes with lower air slowly, so that little of the displaced air is re-circulated in the breeze. In the Clear Lake basin, however, because both processes occur in a relatively small and confined space, these winds are a kind of perpetual motion machine.