Last Saturday, we drove out to the Yakima Valley to visit a few wineries (to be reviewed in the August issue of the Review of Washington Wines). When we left Walla Walla at 8 a.m., the temperature gauge on our car registered 79 degreees. When we reached Yakima, it was 94. We packed a cooler in to trunk to put our wine purchases into. Interestingly enough, most of the wineries had surprisingly good turnouts despite the 100 plus degree temperatures. The next day, Walla Walla hit a high of 113 degrees, the likes of which hasn't been seen in years.

The heat wave is now into its third week. Wildfires have been spreading around eastern Washington, with thousands of acres scorched.

What does all this mean for the vineyards? It's not good. When temperatures reach about 95 degrees, wine grape vines start to shut down in order to protect themselves. This means the plants' energy is going into the vines rather than the grapes, shutting down their maturation. Grapes can also become sunburned. In this situation, watering is critical and requires constant vigilance. Young vines with less leaf canopy are particularly vulnerable. Certain grapes react differently. Syrah shuts down and leaves will turn yellow and fall off. Cabernet Sauvignon and Sangiovese handle heat better. (For a more complete report see Andy Perdue's posting of June 30 in greatnorthwestwine.com).

The end of the heat wave is nowhere in sight. The current weather forecast is for temperatures hovering around 100 degrees for the next two weeks. More later!