Frost again?

Vulnerable.

Once again. Most of our vines have budded out and are now freeze susceptible. The forecast for the next few mornings, especially tomorrow morning is worrisome. A few degrees up or down could make the difference between a full crop and significant losses. This is not the first potential freeze event of spring 2022. Wildly fluctuating temperatures have our heads spinning.

Frost protection was one of the priorities in choosing what is now Hardscrabble Vineyard. The site is located in a thermal inversion zone. During calm frosty conditions, the heavier cold air slips down the slope into the hollow. The lighter warm air is in turn lifted up to our vineyard. This is known as a radiation frost. It is the most common frost and one in which we are well protected because of our topography.

Adjacent to the winery are Chardonnay vines planted in 1985. They grew for 35 years without experiencing frost damage. But the weather is changing. In 2020 we lost about half of the potential crop to the Mother’s Day freeze. We could be facing the same scenario over the next several mornings. These are not classic radiational frosts where the still air allows for stratification. These are cold winds howling in from Canada. Known as advection freezes, our inversion advantage is lost.

Most frost mitigation measures are geared towards radiation frost. Wind machines and helicopters mix the still air. When vineyards are located in low areas (Napa Valley floor or Burgundy), growers try to stir the air to prevent inversions. Burning stuff in the vineyards (smudge pots, candles [pots of paraffin] hay bales, grapevine cuttings) results in a localized blanket of warmth and smoke. But again this only works under calm conditions. Let’s not even get into the resulting pollution and carbon footprint.

Experienced farmers understand their limits of control. This is one of those moments.

We’ll keep you posted.

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Linden Vineyards / Learn More / Latest at Linden | Journal: April 27, 2022