When we started our vineyard in the
Rattlesnake Hills in 1980 the wine grape guru for the state was Jack Watson,
WSU extension agent in Prosser. In 1980 very little was known about wine grape
growing in the state, but Jack knew more than anybody – except perhaps Dr.
Walter Clore who was still alive at the time. When we asked Jack about planting
grapes in Zillah, he was skeptical that it would be successful, after all, Red
Mountain is warm and Prosser is cold, and the further west you go toward the
Cascades, the colder it gets. So went the conventional wisdom.
 |
| Dr. Walter Clore visits Bonair Winery |
In 2004 Sagebrush Ridge or Prosser
Flats as I call it was the center of Washington viticulture with over 11,000
acres of wine grapes. It was and still IS the Yakima Valley. This area was so
notoriously cold that in the 1990s the Washington Wine Commission held ‘cold
climate’ wine symposiums. In retrospect, this seems crazy considering that the
important AVAs in the state are as warm as the Napa Valley.
Then Ch. Ste. Michelle cancelled
red wine contracts in Prosser Flats much to the chagrin of the growers there
who thought their grapes were fine – 23o brix and some pyrazines. (Pyrazines
cause vegetative/weedy aromas in red wine.) No problem.
The Rattlesnake Hills AVA was an
outgrowth of Bonair Winery trying to make non-vegetal reds from the Faire Acre
Vineyard mother block at 1150 feet elevation (just above the Roza Canal) on
Sagebrush Ridge. It was obvious these grapes were different from Rattlesnake
Hills grapes but all had to be labeled Yakima Valley so the consumer couldn’t
distinguish.
At that time the cold climate of
Prosser Flats was a mystery, but I think I have solved it. It is caused by two
features of geography.
First, it sits under Rattlesnake
Mountain 3500 feet tall and having the dubious distinction of being the tallest
treeless mountain in the United States. At 3500 feet, it is tall enough to
generate weather and cold air. This cold air drops into the shallow valley that
sits between Rattlesnake Ridge and Sagebrush Ridge. It easily slides over and through
Sagebrush Ridge (the gap) filling the constricted valley between Sagebrush
Ridge and the Horse Heaven Hills.
Second, the valley between
Sagebrush Ridge and the Horse Heaven Hills is very narrow and fills with cold
air easily up as far as the summit of Sagebrush Ridge.
The Rattlesnake Hills AVA, on the other
hand, is bounded on the north by the Rattlesnake Hills which at their western
end are less than 2000 feet in elevation, not high enough to generate gobs of
cold air. The valley below, the Central Yakima Valley, is 14 miles wide and
never fills very full of cold air.
To further dispel the myth of it
getting colder as you travel west, Red Willow vineyard is on Autanum Ridge (an
extension of the Rattlesnake Hills west of Union Gap) and it is warmer than Prosser
Flats.
As of this writing, the warmest AVA
in the state is Red Mountain followed by the Rattlesnake Hills. Maybe the
Rattlesnake Hills AVA’s identity is obscured by the fact that the area is great
for all wines, red and white, not just red like Red Mountain, but it is definitely
red wine country.
