California vintners brace for an El Niño winter forecast to dump 211% of normal rain on Paso Robles

California winegrowers are preparing for a potentially very wet El Niño winter with a mix of relief and concern, as forecasts point to heavy rain from December through March 2027 across much of the state.

For an industry that depends on limited water supplies, a rainy winter often brings clear benefits. Grapevines are dormant in winter, so rain can refill reservoirs and aquifers, move salts through the soil and help nourish deep roots before the growing season begins. That matters well beyond the vineyard gate. California is a major wine-producing region for the U.S. and export markets, so changes in water availability, soil conditions and vineyard repair costs can shape grape supply and expenses across the beverage sector.

But growers and erosion specialists say the same storms that can recharge water sources can also wash away soil, damage roads, flood access points and, in some cases, harm vines if wet conditions persist too long. Gov. Gavin Newsom declared a state of emergency in October as California prepared for possible flooding and power outages tied to the weather pattern.

Gregg Hibbits, a longtime grower in San Luis Obispo County, said rain is usually welcome in viticulture. His company, Grapevine Capital Partners, oversees more than 3,000 acres of vineyards, many of them in Paso Robles. But he said a powerful El Niño creates an “inherent conflict” for growers because the same rainfall they want can turn destructive if storms are too intense.

Paso Robles is forecast to receive 211% of its typical rainfall between December and March 2027, according to the forecasting model cited in the report. Santa Barbara is projected to receive 226% of its usual rain, and the Santa Rosa area 173%. Hibbits said warmer, drier regions can be especially exposed because their soils are less accustomed to absorbing large winter storms.

The main concern for many growers is erosion. Fast-moving water can strip topsoil, undermine vineyard rows and damage stakes and irrigation systems. In a severe case, Hibbits said, flooding could wash out enough of a site to make a vineyard unusable.

Rich Casale, an erosion specialist with the U.S. Department of Agriculture’s Natural Resources Conservation Service, said he has seen major damage from a single storm. He recalled visiting a site near Healdsburg where a prepared but not yet planted vineyard failed after heavy rain. Because the slope had been deeply tilled, he said, part of the hillside gave way and about 2.5 acres were lost.

Casale has spent recent weeks visiting vineyards and other farms to discuss storm preparation. He said common protections include jute netting, plastic tarps and mesh tubes filled with straw, all intended to slow runoff and hold soil in place. But he warned that many of those measures are installed incorrectly or placed in the wrong part of a property. In some cases, he said, they can worsen drainage or move problems elsewhere.

He said the most reliable defense is cover cropping. Plants grown between vine rows, including mustard, sweet peas and radishes, help anchor soil with their roots and can also improve soil health. Newly tilled ground is usually more vulnerable because loose soil washes away more easily. Casale said younger vineyards therefore face greater risk in a wet year.

Despite the concern, recent experience suggests flooding does not automatically mean severe vineyard damage. When atmospheric rivers hit California in 2023, they cracked roads and flooded many urban areas, but vineyards were largely spared major losses. Photos of vines standing in winter floodwater can look alarming, growers say, yet short-term flooding during dormancy is not always harmful.

In Northern California, where winter flooding is more familiar, some growers are more concerned about damage around the vineyard than damage to the vines themselves. Kendall Hoxsey-Onysko, president of Yount Mills Vineyard in Napa Valley, said her biggest worry is flooding that affects roads and workers’ homes. She recalled her family’s Yountville home flooding in 2006.

The risk shifts if wet conditions stretch too far into the growing cycle. Allison Jordan, vice president for environmental affairs at the Wine Institute, said the early end to the 2026 harvest should give many growers more time to prepare fields before heavy storms arrive. But if vines begin to bud as early as they did in spring 2026 and flooding continues through March 2027, excess water could limit oxygen to the roots and interfere with flowering.

That timing matters for production. A winter that restores groundwater can reduce irrigation pressure in the following season, especially in dry areas such as Paso Robles. But if storms strip surface soils or cut off vineyard access, growers may face higher labor and repair costs at a time when California’s wine sector is already dealing with oversupply and weak margins.

Cynthia Lohr, co-owner of J. Lohr, said El Niño can be a double-edged sword in places where water is scarce. Her company farms more than 2,600 acres of vineyards in Paso Robles. Growers there want enough rain to rebuild the water table, she said, but not so much that the top layer of soil is carried away.

Some vineyard managers are focusing on directing water rather than resisting it. Hilary Graves, manager of Booker Vineyard in Paso Robles, said she plans to chisel channels into the soil so rainfall can pool and soak in rather than run off the property. For growers who can control erosion and drainage, a wet winter can still be an advantage, even in a season when California is bracing for wider storm damage.