Angara river is the only river flowing from Lake Baikal. It is amazing that it never freezes, even during coldest time of winter. It is the only winter-stay for birds in Northern Asia. It happens because of natural reason: water in the lake changes temperature only at its upper part, it stays the same all year round deeper than 300-500 meters (depending on season) and it’s 4 C. At the beginning of the river the water flows from the bottom layer. That’s why it takes at least 2 kilometers to cold it down enough to freeze.