(Wines&Vines) - While most West Coast winegrowing regions bask in what looks to be another boom year, vineyard conditions east of the Rockies have been neither uniform nor uniformly favorable during the 2013 growing season.

Colorado: Cooler than ever

 It’s no surprise that much of Colorado is considered a “cool climate” for viticulture, but the winter of 2013 left many vineyards in the Grand Valley, the state’s most productive region, with a potential crop loss of 30%-50%.

“Time will tell,” said Horst Caspari, viticulturist at Colorado State University’s Western Colorado Research Center. “If you’re dead in the winter, spring weather won’t make any difference,” he told Wines & Vines. After a month when temperatures never got above freezing, the mercury dropped to 0°F on Jan. 15, when most of the damage was done to dormant vines in the Grand Valley.

Hard freezes recurred on several occasions, an increasingly frequent occurrence, but contrary to traditional weather patterns. During three of the past four years, Caspari said, the temperature fell to 0°F, compared to only one time in the 10 years prior.

 “If Grand Valley has a bad day, the Colorado wine industry has a bad day,” he said. The research station is working on methods for winegrape growing in cold climates, but that’s a generational endeavor.