Lake Baikal

A lake in a crack in the continent

Lake Baikal fills a rift valley in southern Siberia, where the Earth's crust is slowly being pulled apart. The rift began opening about 25 to 30 million years ago, which makes Baikal the oldest lake known. Most lakes fill with sediment and vanish within tens of thousands of years. Baikal survives because the rift keeps widening and deepening faster than it can fill.

The lake reaches about 1,642 m deep, the deepest of any lake on Earth, and beneath its floor lie several kilometers of sediment. The basin is still active: small earthquakes are common around its shores.

A fifth of the world's fresh surface water

Baikal looks long and narrow on the map, about 636 km from end to end, but its depth gives it enormous volume. It holds about 23,600 cubic kilometers of water, roughly a fifth of all the unfrozen fresh water sitting on the planet's surface, more than all five of North America's Great Lakes combined.

More than 300 rivers flow in, but only one, the Angara, flows out. The water is famously clear, and in places you can see many meters down. Tiny crustaceans in the lake help keep it clean by filtering algae and bacteria.

Life found nowhere else

Millions of years of isolation have produced a remarkable set of species. The best known is the nerpa, or Baikal seal, one of the only seals in the world that lives entirely in fresh water. How its ancestors reached a lake in the middle of Asia is still debated. The lake also holds the golomyanka, a translucent fish that gives birth to live young, and many endemic snails, sponges and crustaceans.

Baikal became a UNESCO World Heritage Site in 1996. Pollution from industry and towns, along with warming winters and changing ice, are ongoing concerns for scientists who study it.

Ice and summer seasons

In winter the lake freezes over, usually from January into May. February and March are popular for walking, skating and driving across the clear blue ice, which cracks and booms as it shifts. Only use routes marked by locals, because thickness varies and open cracks can appear.

July and August bring the warmest weather for hiking the shoreline trails, boat trips and visits to Olkhon Island, the largest island in the lake and a sacred place in Buryat tradition. The water stays very cold year round. Irkutsk, near the southern end, is the usual starting point. Check current travel advisories before planning a trip to Russia.

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