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In May of this year, vineyards covering thousands of acres across California found themselves at the mercy of mother nature once again, leaving the fate of the 2019 vintage in limbo. An extreme, unseasonal weather pattern ripped through the West Coast, just as many vines had begun to bloom, entering some of the most sensitive weeks of their annual growing cycle.  

Seasonal Variation in Bloom Timing & Duration

There are several elements that impact bloom timing and duration regionally every season, including rainfall, temperature, radiation, and elevation. Different grape varieties stagger their bloom over the course of the late spring, some shooting out their anthers and stigmas in early May, and others in June. Throughout the North Coast in both 2011 and 2018, varieties that tend to bloom early flowered unusually late, well into the last week of June, as opposed to vintages 2013-15 that primarily bloomed in the first half of May.

The timing of bloom is critical, especially in vintages with extreme weather events. A storm or cold front could cause shatter, resulting in reduced yields in some varieties, while leaving those with more gradual phenological development unaffected. Because of this annual variance, proper tracking of block-level phenological development is crucial in evaluating the impact of different weather events on yields.

March Temperature Impact Bloom

The Effects of Low Spring Temperatures

The 2019 spring season kicked off with temperatures 3°F cooler than average in March. This weather contributed to a two-week delay in budbreak across California, ultimately shifting the vulnerable window of bloom for many varieties to be later than usual. Followed by unseasonably cold temperatures in May, along with rain, strong winds, and hail, some early blooming varieties In Northern California, like Chardonnay and Pinot Noir, found themselves grasping on to their freshly opened flowers for dear life.

In Sonoma County, daytime temperatures dropped 20°F below the historical average and 10°F lower than 2010, which previously held the title for the year with the coldest May temperatures since the turn of the millennium. Both high and low temperatures crept worryingly close to the historical lows set decades ago. These extended irregular temperatures were served with a garnish of 22 MPH winds and four inches of rain, at times morphing into hail. This “perfect storm” of phenological development timing and a unique brew of weather elements has historically led to decreased yields of nearly 20% in previous vintages.

Pinot May Temperature vs Yield

Chardonnay May temperature vs yeild

With conditions forecasted to dry up and temperatures on the rise again, these vines will begin fruit set in the coming weeks, and cases of shatter will become visually apparent and quantifiable in the vineyard. Only then will growers, vineyard management companies, traders and wineries begin the enormous task of evaluating the damage. With harvest less than three months away, these estimates will ultimately dictate crucial business and farming decisions, determining many companies’ profitability for the 2019 vintage. Given such conditions, it is especially important to gather and analyze vineyard data, as timely and accurate projections will allow growers and winemakers to operate more precisely at optimal profit margins.

Weather in a Soft Market

These recent events certainly did not take place in a vacuum. The 2019 season comes on the coattails of the epically large 2018 vintage, which in many cases exhibited yields 35% above the historical average. Unfortunately, this increase coincided with a sudden nationwide drop in wine consumption by over 1%, after many years of consistent annual growth. This collision has caused an unusually soft market, placing tremendous pressure on both growers who are facing low market prices and wineries which have overflowing inventories.

In years like this one, when the grape and wine industry is flirting with disaster, seasoned professionals just shake their heads and say, “welcome to agriculture!” As always, in order for growers and wineries to navigate these stormy waters effectively, their decision-making must be leveraging the most accurate, real-time and high-resolution information.

Uri RosenzweigExpert Editorial
By Uri Rosenzweig, Senior Product Manager, Trellis.ai

Trellis is harnessing the power of AI to provide the insights and forecasts growers and food and beverage producers need to lower production costs, improve quality and minimize loss across the supply-chain. 

For more information about Trellis www.trellis.ai

 
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