Lake Tahoe - the legend

Lake Tahoe is known by the people as the giant lake in the mountains where coyote, bear, deer and elk are abundant. During the spring several tribes travel up to the Lake to hunt and celebrate. The whole summer the people enjoy the cool and sunny weather, the crystal clear water and live of the earth. As the cold season starts the people migrate to lower and warmer parts. During the long winter Lake Tahoe changes into a white, pristine world where only a few coyote and bear survive. A thick layer of powerdy snow covers the mountains and the high valley on the shores of the Lake.

In the year of the falling bear one young man of the Navarro tribe decided he wanted to stay near the Lake during the winter. The tribe discouraged him, and the elders told him there would be little game and no plants to survive. The young man, Niska, knew all this, but was stubborn and thought when coyote can survive, I should also be able to survive. Besides, he did not have to support a family and his curiosity for the Lake during the winter won his fear.

Niska was well prepared. He had good clothes and boots made of buffolo leather. He had gathered nuts and dried fruits and stored them in a few secure places, just like the squirrels. Winter set in and Niska....

The Lake that does not get frozen

Lake Tahoe
Nowadays Lake Tahoe is known as a holiday area which is attractive both in summer as well as during the winter. The Lake is deep blue, crystal clear and can be viewed from the high surrounding mountains of the Sierra Nevada.

In winter the temperatures hardly ever get above freezing point. If so it is only for a few hours on a sunny day. So you would expect the Lake to be frozen over, covered with ice and snow. However, I noticed that the Lake has a very peculiar feature: the water does not get frozen!

What is the reason? What chemical substance has the water, that it does not get frozen? Are there special currents in the lake? Is the water temperature too high, may be due to volcanic activity deep down in the lake?

I try to figure out a few things with just my senses. First, I observe that the river that flows from the Lake into a valley has ice on it's shores even though the current in the stream is quite strong. Though the water from the Lake has the capacity to turn into ice.
I walk to some piers that stretch above the Lake. The water is very still, no currents and no wind that disturbs the surface of the water.
I step down to the water and taste it. It does not taste salty at all. It tastes purer that pure water in the sense that it does not have taste. Apparently, there are very few minerals in the water.
A closer look at the water gives more information: I cannot discern any plants, or animal life in the water. There seem to be no algae.

I still have not found a reason why the water in the Lake does not get frozen.