Lake Suwa is a lake in the Kiso Mountains, in the central region of Nagano Prefecture, Japan.
Lake Suwa is the site of a natural phenomenon known as the "God's Crossing" (御神渡り, o-miwatari), large cracks that form in the winter across the surface of the frozen lake. A vertical temperature gradient results in ice pressure ridges forming in the surface ice, reaching heights of 30 centimetres (1 ft) or more.[1]