The Santa Ynez Valley has the greatest concentration of wineries in Santa Barbara County. Prior to Prohibition, the valley had as much as 5,000 acres under vine, but it was not until 1969 that commercial viticulture returned to the region. The long valley is bordered by the Purisima Hills and San Raphael Mountains to the north and the Santa Ynez Mountains to the south. The western section benefits from the moderating effects of the Pacific, and is dominated by Chardonnay and Pinot Noir. As one follows the Santa Ynez River east, the elevation rises approximately 800 feet. At this higher altitude, in north-south running canyons, vineyards experience higher diurnal temperature fluctuations and a warmer overall climate. In this environment, Syrah is leading the charge for "Rhone Ranger" wineries in the area.