The Austrian Grüner See, the lake that fills up only 4 months a year.

This time i want speak about the Grüner See (in english Green Lake), a lake in Styria, Austria in a village named Tragöß, surrounded by the snow-capped Hochschwab Mountains and forests.
The emerald green waters of this mountain lake offer the chances to do some of Austria’s most unusual dives, in this nation not particularly famous for scuba diving.
But apart from that, something unique happens in this lake.
You can find fish swimming among the benches and the branches of the trees, or small crustaceans sheltered among the blades of grass. And what is the reason for so much strangeness? In the lake there is water only in the summer months, when the snows of the high Austrian glaciers melt and fill the water catchment, and during the winter months the same place is a destination for hiking and mountain walking. In fact, during the winter months the area is almost completely dry and is used as a natural park, and when temperatures rise the ice and snow of the snowy peaks of the mountains above melt and the park is filled with a cold crystal water, which owes its peculiar green color from the grass and the underlying leaves.
The lake reaches its maximum depth of around 12m from mid-May to June and is claimed to look the most beautiful at this time. In July, the water begins to recede.
The temperature of the water in its hottest moment reaches only 7 degrees Celsius, a real icy pool, not the best for bathing, but incredible for discovering a unique underwater world of its kind.

Photos from the web except the first one.