In simple terms, how was the Okanagan Lake formed?

1. 50 to 60 million years ago rock forming the crust of the earth
broke apart and formed a large valley.

2. Then volcanoes erupted along the valley.

3. A huge river then began to erode the valley.

4. Mountain building forces developed and central B.C. uplifted.

5. An ancient drainage system developed, 200 to 300 meters relief.

6. Uplift continued; uplands were inundated with plateau basalt filling existing valleys.

7. A gradual climate change occurred causing an Ice Age.

8. Large glaciers moved over the land, gouging out the valley and overtopping the volcanoes and rounding off the sharp edges. A number of glaciations are apparent.

9. When the last glacier melted, the valley was dammed by glacial deposits and water collected behind the dam. Some of the water flowed to the ocean, but some collected in the gouged out valley and forms Lake Okanagan today.

Also please see "Geology of Bear Creek Canyon" Naramata Field Trip, Geology of Mt. Boucherie Volcanic Complex, Geology of the City of Kelowna and Origin of the Okanagan Valley, British Columbia.