Hills of solid ice
On the flat tundra of the Tuktoyaktuk Peninsula, dozens of conical hills punctuate the landscape. These are not ordinary hills of rock and soil; they are pingos, mounds with massive cores of solid ice. The Tuktoyaktuk region contains the world's highest concentration of these formations, with approximately 1,350 in total. The Pingo Canadian Landmark, a 16-square-kilometer protected area, includes eight of these structures, including Canada's tallest, Ibyuk Pingo. Ibyuk stands 49 meters high—about the height of a 15-story building—with a base 300 meters in diameter.
The pingos here are almost all "closed-system" or hydrostatic types. They form in the beds of former lakes. Arctic lakes often do not freeze to the bottom, creating a lens of unfrozen, water-saturated sediment called talik, insulated from the surrounding permafrost. When a lake drains, this insulation is lost. The surface begins to freeze, and permafrost advances inward, squeezing the trapped water. Unable to escape, the pressurized water pushes upward, heaving the overlying layer of frozen ground into a dome. This process is slow; Ibyuk Pingo grows only about 2 to 2.3 centimeters per year and is estimated to be around 1,300 years old.