This intriguing phenomenon is not in fact not the result of the supernatural, but an organic occurrence (though this doesn’t detract from its mystical atmosphere). This disappearing and reappearing act is caused by the temperature rising and falling throughout the year, causing the snow that gathers in the basin to melt and fill the lake with shimmering emerald waters.
The water is at its most shallow, and the lake at its most inconspicuous, in the winter months (around just 1m–2m, or 3.2 ft.–6.6 ft.), when the surrounding areas become populated by hikers. It begins its transformation into an oasis around springtime, swelling to its maximum capacity of 12m (39 ft.), and becoming a temporary paradise before it recedes once more.
Because the water’s appearance is so striking; a glossy, glassy, green hue – it has become somewhat of a honeypot for beady-eyed Instagrammers, who gather like flies to capture this beautiful scene (#nofilterneeded, etc). Snap-happy scuba divers, who enjoy unobscured vision beneath the surface of the lake, populate the lake’s shores, suddenly making the Grüner See a popular tourist magnet.
However, although the lake may be picture perfect, the attention that the Grüner See garners has sparked concerns over the protection and preservation of the land, as the activity caused the water’s colour to become murky. Therefore, restrictions were applied in 2016, prohibiting water sports from taking place on the lake. Swimmers may be wary as it is; because the water comes from snowmelt, it is extremely cold (4°C–8°C, or 39.2°F–46.4°F degrees), therefore acting as a natural deterrent.
Despite these constraints, the lake is mesmerising to observe from afar, and its ever shifting, transformative nature makes it all the more alluring.