RV Lifestyle As the last glaciers melted about 10,000 years ago, the meltwaters created the silt benches between Penticton and Naramata (that are now renowned for their fine vineyards), as well as the sandy benches of Oliver and Osoyoos that are so ideal for the noble grape varieties. The Okanagan lies in the rain shadow of the Cascade Mountains. Pacific storms, pushed by westerly winds, are wrung dry as they ascend the cold coastal slopes of these high peaks. As the air descends into the Okanagan, it is relatively warm and dry; often, the only local signs of a storm bringing torrential rain to Vancouver and Seattle are grey skies and a brisk southerly wind on Osoyoos Lake. As a result, the south Okanagan receives only 30 cm of precipitation each year – about the same as Tucson, Arizona. The cold Canadian winters are strongly moderated by the large lakes in the valley, and vintners needing to harvest icewine grapes at -8 °C are often forced to wait for the coldest night in January. The summer beach experiences and tree-ripened fruit are still part of the Okanagan’s unique charm. McIntyre Bluff at the south end of Vaseux Lake Skaha Lake looking north to Penticton and Okanagan Lake beyond SS Sicamoos moored on Okanagan Lake at Penticton Then, about 55 million years ago, the collisions subsided and the monumental pressure that had been pushing eastward throughout British Columbia eased. This relaxation created deep cracks throughout the province, among them the newborn Okanagan Valley. The ancient rocks that had once been the continental shelf of North America, long buried by Quesnellia, rose to the surface. They now form the cliffs along the east side of the Okanagan, as well as the massive McIntyre Bluff that forms the west wall of the valley at the south end of Vaseux Lake. Volcanic activity was common during the birth of the Okanagan, creating mountains throughout the central Okanagan including Knox Mountain in Kelowna, Giant’s Head in Summerland and most of the hills around theWhite Lake Basin northwest of Oliver. The final geological touch in the shaping of the valley came two million years ago, when the valley was covered by a series of ice sheets. The Pleistocene glaciers rounded off the local mountains and brought massive amounts of sand and gravel to the valley bottom. CSANews | SUMMER 2017 | 25
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