Kalamalka Lake, Lake near Vernon, British Columbia, Canada

Kalamalka Lake is a large lake near Vernon in British Columbia, known for water that shifts between vivid blue and green depending on the season and time of day. The lake runs roughly north to south, with rocky hillsides on one shore and flatter, sandy stretches on the other.

Kalamalka Lake is fed mainly by Wood Lake to the south, linked by a canal at Oyama, and drains north through Vernon Creek into Okanagan Lake. It takes its name from the Okanagan First Nation chief who occupied its northern shores. The lake lies about 4 kilometres south of Vernon and supplies the city's main drinking water.

The lake is named after an Okanagan First Nation chief who occupied its northern shores, and locals shorten it to 'Kal Lake'. Its beaches include Kal Beach and Cosens Bay Beach in Kalamalka Lake Provincial Park, plus Jade Bay, Juniper Bay, Kekuli Bay, Kirkland Park and Kaloya Regional Park Beach. The water's cyan-to-indigo shifts earned it the name 'lake of a thousand colours'.

Several beaches along the shoreline are easy to reach by car and offer parking, restrooms, and picnic areas. For the best view of the water's color changes, plan to visit in summer during the early morning or late afternoon when the light is low.

The colour comes from calcium carbonate precipitating in the water as phytoplankton photosynthesise in warm weather, which raises turbidity and can leave a crust of calcium carbonate on shore vegetation and charophytes. Because the lake mixes fully from fall to spring and stratifies from May to early November, different parts can show cyan and indigo at the same time, hence the name "lake of a thousand colours".