Around the Lake, mountain waves are common. Analogous to the waves in a creek downstream from a submerged rock, the mountain waves are undulations in the airflow as a result of the wind blowing over a mountain. Usually, the visual evidence of mountain waves is the appearance of wave clouds (with their characteristic, smooth, lenticular shape). But, now and then smoke from a forest fire reveals the waves.
The Kootenay-Lake Website offers a discussion and more pictures of the local wave clouds.
Smoke from a distant forest fire flows over the mountains around the Lake and is carried up and down by the mountain waves.