The Spotted Lake of British Columbia: The Lake That Dries Into Polka Dots Every Summer

There is a lake in British Columbia’s Similkameen Valley that, for most of the year, looks like any other body of water. Then summer arrives, temperatures climb into the high desert heat, and the water starts to evaporate. What it leaves behind is one of the strangest surfaces in North America: hundreds of shallow circular pools, each a different color, separated by white mineral walkways that form naturally between them. Green pools next to blue ones next to yellow ones, covering the whole lake like a painting someone made and then left outside.

The lake is called Kliluk by the Syilx Okanagan Nation, who have considered it sacred for thousands of years. Most visitors know it as Spotted Lake. Both names are accurate. The spots are real.

Why It Happens

The lake sits in a natural basin with no drainage outlet. Groundwater and precipitation flow in. Nothing flows out. The water that accumulates contains an unusually high concentration of minerals: magnesium sulfate, calcium sulfate, sodium sulfate, and smaller amounts of eight other minerals, plus traces of silver and titanium.

In winter and spring, the water level is high and the lake looks normal. As summer heat intensifies and the water evaporates, the minerals concentrate and crystallize. Magnesium sulfate, which is essentially Epsom salt, crystallizes at the surface of each pool and gives it color. The specific shade of each spot depends on the particular mineral mix at that location and the amount of precipitation that year, which is why the colors vary not just between spots but between seasons. The same pool runs green one summer and yellow the next.

Additionally, as the minerals crystallize, they form natural ridges around and between the pools. These white mineral walkways are firm enough to walk on during peak evaporation. The whole surface organizes itself into something that looks designed, a mosaic of colored pools with pale borders, covering what was recently open water. By fall, when rains return and the water level rises, the spots dissolve back into the lake.

What the Okanagan Nation Used It For

The Syilx Okanagan people have lived in this region for at least 3,000 years, and Kliluk has been a central site throughout that time. The lake holds deep spiritual significance for them. Oral tradition describes each of the approximately 365 pools as having specific and distinct healing properties, one for each day of the year. The therapeutic mud and mineral-rich waters were used for centuries to treat aches, wounds, and various ailments.

During World War I, the mineral value of the lake attracted a different kind of attention. Workers harvested the magnesium sulfate and other salts daily to support ammunition and explosives manufacturing. The wartime extraction stripped significant quantities of minerals from the lake, and some accounts suggest the lake produced a wider variety of colors and more vivid spots before this period of industrial removal.

For much of the 20th century, the land around the lake passed into private hands. In 1979, a private owner proposed turning the site into a spa. The Okanagan Nation opposed this vigorously, and with government support, the development was prevented. In 2001, the Okanagan Nation successfully acquired the land. The lake now belongs to the Okanagan people, protected from commercial development and managed as both a cultural site and an ecological one.