(Eater) - In 1998, heavy rains hit California mid-winter in what was described as one of the strongest El Niños to date. It caused flooding, abnormally high waters, and multiple storms that led to substantial damage. That year, the wine was different, too.

Winemakers at the time prepared for what they knew was going to be a rough year. Vineyards, indeed, do need rain. But extreme, uncontrolled, and prolonged showers are hard on any crop — especially so for wine grapes. Sure enough, after the 1998 vintage was bottled and sampled, critics furrowed their brows: The wine was different, less bright, and simply not as good as years past. The likely scapegoat was the strong El Niño, but was this climate phenomenon really to blame for a lackluster vintage?

In 2016, the West Coast faces a similar reality. Yet again, 'tis the season of El Niño, aptly named with a Spanish flair for its arrival's proximity to the birth of the central figure of Christianity. The impending severe weather may be welcomed with more open arms than in the past, due to the drought in California. But the change in weather patterns will yet again affect how crops develop and transform into consumable goods.

The effects of an onslaught of winter rain are hard to predict for this year's wine crops. Harsh weather conditions could forever besmirch 2016 vintages, or rains could revive parched soils. Weasked the leading wine and climate experts what havoc this winter could wreak.

Meet El Niño

El Niño events — which bring about heavy rains and cooler days — tend to occur every three to eight years, but not every event is created equal. This particular El Niño, however, is receiving an unprecedented amount of media attention because of the severe drought that has plagued California. "There has never been a drought in the history of the world that has ever received as much attention as this drought," says Dr. A. Park Williams, a bio-climatologist at the Lamont-Doherty Earth Observatory of Columbia University. Williams's work combines climatology and ecology with a particular focus on the consequences of drought. "The world is watching California," he says.

This is because what El Niño brings to the West Coast and Southern U.S. is rain, and a whole lot of it. El Niño may sound like an alarming prospect, but for winemakers, it's just one of dozens of climate factors that influence their vintages. According to Christopher Howell, winemaker at Cain Vineyard in St. Helena, California, fine wine's sensitivity to the climate is intrinsic in the product's definition. Each year, inclement weather presents new challenges for vintners. If handled correctly, these factors are the alchemy that yield a great wine. But as weather events get more and more extreme, growers are faced with new challenges on the journey from vine to glass.

El Niño Years Bring Rain to Napa Valley Harvests

California and Napa Valley have been struggling for rain in the past few years. But history shows years with moderate to very strong El Niños (1998, 2003, 2010) bring more rain to the winemaking region during grape harvests.

Does El Niño damage the grapes?

In the spring of 1998, Southern California saw cooler weather and a lot of rain. This was less than ideal for the vines, which bud in spring when temperatures rise above 50 degrees. In fact, the weather was so atypical that growers almost thought the vines wouldn't flower. According to Mia Klein, founder and winemaker at Selene Wines in Napa, California, the late flowering and harvest made for a unique vintage "not as bright" as the previous year. 1997, in contrast, was widely heralded as a great vintage for the Napa region. In 2003, the New York Times described the '97 batch of Napa wines as "rich, beautifully balanced wines."

When bottles from '98 were first uncorked, says Marika Vida, sommelier and wine director at the Ritz-Carlton in Manhattan, "it got panned." Take, for example, the reviews of Joseph Phelps's 1998 Cabernet Sauvignon. Wine Enthusiast, in its review of the vintage, described it as having an "almost sulfurous quality" with "off-putting aromas" to boot. (The year prior, the same vineyard's output was heralded as one of the best in years.) Fine-dining establishments, said Howell, even refused to order '98 wines, and it begged the question whether global climate events like El Niño would cause systematic negative effects for the industry.