Who ever notices a mirage on the Lake?
Once I took pictures of mirages at the Coast and then included them in an article. A reader responded that everyday for years she went for a walk along the beach, but had never seen a mirage over the water. Now, as a result of my article, she couldn’t stop seeing them; they abounded.
Mirages certainly abound on Kootenay Lake; few days are without them. And, I always find them fun to watch. So it was a couple of days ago during a walk at Kokanee Creek Provincial Park: I found myself admiring both the Purcells covered in snow and the Harrop ferry transformed by mirage.
The Kootenay-Lake Website offers more pictures and discussions of local mirages.
The first picture, below, shows the overview of the Purcells and the ferry. The second picture is an enlargement of the ferry. What looks as if a reflection, isn’t. Not only is the Lake too rough to give a simple reflection, but the lake surface cannot even be seen at the distance of the ferry. There is a slowly ascending optical surface (called a caustic), below which nothing—lake surface, ferry hull, distant beaches—can be seen. Objects which extend above the caustic are doubled: seen right way up, seen upside down. The ferry seems to float along through the air. This is an inferior mirage and the temperature difference between the air and water on this occasion was about 6°C.
