The Increasingly Frequent Threat of Frost

American grapegrowers have yet to pick a single grape, but it’s already clear there will be less Pinot Noir this year. Record-low temperatures struck Oregon’s Willamette Valley—down to 26° F in some areas—in early April, just as the vineyards were starting budbreak. Frost isn’t uncommon in Oregon, but it typically strikes earlier in the season when vines are still dormant. “We have never seen such cold temperatures so late in the season,” vintner Josh Bergström told Wine Spectator.

- TIM FISH AND AARON ROMANO

To the south, California’s Central Valley and eastern foothills experienced their worst frost in recent years, inflicting widespread damage. After a storm front blew through in the early morning hours of April 12, the dew point dropped and temperatures plummeted. “We were experiencing 90° F temperatures three days before,” said Stuart Spencer, executive director of the Lodi Winegrape Commission.

Frost is a perennial threat to vineyards, but in recent years, the risk of damage to young buds and shoots has risen. A changing climate has led to warmer temperatures earlier in the year, waking vines from their winter slumber and triggering budbreak. Instead of still being dormant when sudden cold snaps bring frost, vines are in their most delicate stage.