1994 Yukon Nuggets

Emerald Lake

In the old days, as we old timers like to succinctly say, things were different. Yep, when we used to make a rare trip to Carcross on the winding, narrow dirt road, we rarely stopped to take pictures at Rainbow Lake.

That’s what we used to call this most photographed of all Yukon scenes. There weren’t many tourists around in the fifties and we had precious little interest in taking pictures anyway. Getting to Carcross - fast - was the main goal. I forget why!

Today, of course, that most photographed location is called Emerald Lake. I don’t know when the name changed from Rainbow to Emerald. Anyway, it is a favourite photo-op because of the gorgeous blue-green colour. Why does Emerald Lake look like that? Well, scientists who study such things explain it this way.

The colour is created by sunlight reflecting off a white layer of "marl" on the lake bed. Marl is calcium carbonate clay that forms in the water and then settles onto the lake bottom. It forms when the carbonate from dissolving limestone reacts with calcium in the water.

The limestone, in the surrounding hills, was created about 200 million years ago in a shallow sea. Imagine what it was like around here two hundred million years ago.

The valley of Emerald and Spirit lakes - now known as the Watson River Valley - was at one time covered by a glacier during the last ice age. These lakes formed when the glaciers retreated about 14,000 years ago.

Retreating ice deposited limestone gravel, eroded from the surrounding hills, onto the valley floor. The carbonate rich gravel eventually led to the formation of marl in the lake. Thus, the colour of Emerald Lake.

Got that? Good! So the next time you stop to take a picture on your way to Carcross, impress your travelling companions with the story of why the beautiful Emerald Lake looks the way it does.

 

A CKRW Yukon Nugget by Les McLaughlin.