Cameron Winery -- sustainably farmed, non-irrigated, Oregon pinot noir and chardonnay

With our climate progressively changing year to year, one phenomena that is starting to occur fairly regularly is an occasional bout of intense winter cold. This seems to be related to the polar vortex (a large area of low pressure and cold air surrounding the north pole) occasionally breaking down and allowing frigid arctic air to descend south. The timing of these “cold snaps” is critical to their ability to inflict damage in the vineyard.

In the Fall, as the vines go dormant, both water and nutrients flow from the canes into the trunks and roots. By mid-winter, grapevines are therefore fairly resistant to winter cold damage because with less water in the tissues, freeze damage is mitigated.

Grape buds have also evolved to survive the cold by developing 3 different types of buds: the primary bud is responsible for the shoot that will develop in the spring and eventually produce clusters of grapes. However, if that bud is destroyed, below it is a secondary bud that will grow only if the primary bud dies. Even further down in the primordial bud tissue is a tertiary bud that is “the bud of last resort”. Secondary buds can produce some minimal quantity of fruit but tertiary buds are concerned only with survival of the vine, so do not produce crop.

In January 2024, we experienced two weeks of extremely cold weather in the Northwest. Temperatures in the Willamette Valley descended to 10-14 degrees Fahrenheit at low & moderate elevations and as low as 4F in higher altitude vineyards. Since the cold occurred in mid-winter, when the vines were dormant, we expect very little bud damage at those temperatures. Damage to the phloem tissue (which carries sugar from the leaves to the rest of the vine) in the canes and trunks  likely did occur to some extent, however minimally damaged phloem can be repaired by the vine.  For the most part, vineyards in the Willamette Valley are probably okay. It’s just too early to know for sure.

However, to our north in Eastern Washington and especially the Okanagan Valley of British Columbia, cold damage was extensive. Temperatures in the Okanagan plummeted to temperatures as low as -20F (-28C).  The grape-producing primary and secondary buds were killed by this deep freeze. That means an almost complete loss of the 2024 vintage. Hopefully, the vines can rebound and produce grapes in 2025. If not, and vines are dead, they will need to be pulled out and replanted. Our hearts go out to our fellow vineyardists.

Now, as we head toward spring in the Willamette Valley, and temperatures rise and days lengthen, our vineyard will begin to awaken from its dormancy. Buds will begin to swell and push out new leaves as nutrients and water start flowing upwards from the trunks and roots. Along with this, cold hardiness will begin to wane.

In 2022 we experienced extreme cold weather in April, just as vines at lower elevation were breaking bud. Crop in these areas was mostly destroyed while those vines at slightly higher elevation were spared the damage since they were not as far along in bud development. So, though we seem to have survived the January cold, now we wait for what will come with bud break!!

Stay tuned.