Zonda, Diablo, Nor’wester, Chinook: The Foehn Winds of Wine

Advanced students of wine can name them: the Zonda winds of Argentina, New Zealand’s Nor’westers, California’s Diablo, and the wild Chinook winds of Oregon. These are foehn winds—warm and dry, sometimes fierce and hot—that periodically rush down the leeward side of a mountain range after the air has dropped its rain on the windward side and climbed up and over the peaks.

Other areas in the wine-producing world that are affected by foehn winds include Alsace, the Jurançon (Southwest France), Switzerland, Washington State, northwest Italy, Catalonia, Lisboa (Portugal), Cotnari (Romania), Valencia, and Málaga. To simplify the concept, think of it this way: any place that benefits from a rain shadow provided by a large mountain (or mountain range) can also be in the line of fire for the foehn.

The well-known Zonda wind of Argentina, experienced most acutely in Mendoza, La Rioja, and San Juan—where the Andes reach their highest peaks—is the perfect, illustrative example. It all begins with the cool, humid breezes off the Pacific Ocean that head towards Chile, coming in from the west. As they reach the shore, they drift inland along Chile’s numerous river valleys, allowing the fog and cool air to penetrate inland. Eventually, the air mass bumps up against the Andes and begins to drift higher and higher.

As the air lifts, it expands and cools. Clouds begin to form as the air becomes laden with water vapor. As the clouds become saturated, the moisture condenses, and it begins to rain or snow. This activity allows for the release of latent heat, and by the time the air mass reaches the peak of the mountain it is cool and dry.

Above the mountains, the wind can be bounced about by mountain air waves—changes in the air flow sometimes referred to by the frankly terrifying name the turbulent vortex—and flung downward, assisted by variations in air pressure.

As the air rolls downhill, it quickly warms up, assisted by the warmth on the ground and the sunshine on the leeward side of the mountains.  Further downslope, the increase in air pressure coaxes even more heat into the air and by the time it reaches the foot of the mountains, it is warm, dry, and ready to roll.

Foehn winds can be beneficial to vineyards; a nice, warm breeze can reduce the risk of mold- or fungi-related vine diseases, and otherwise help keep a vineyard healthy and dry. However, In the extreme, a foehn wind can shake, rattle, and roll a vine enough to cause physical damage. If the wind lasts for more than a few days (which is not unusual), the vineyard’s human inhabitants often complain of nervousness, headache, difficulty sleeping, and irritability.

Another good reason to keep your eye on the weather!

Note: Foehn winds were first studied in the European Alps, and are often referred term as föhn winds, after the original German.

References/for more information:

• https://www.britannica.com/science/foehn
• http://www.eniscuola.net/en/argomento/air-in-motion/winds/the-foehn-wind/
• https://www.weatheronline.co.uk/reports/wxfacts/The-Foehn-foehn-wind.htm
• http://fineswisswine.ch/swiss-wine/foehn

The Bubbly Professor is “Miss Jane” Nickles of Austin, Texas… missjane@prodigy.net