When Lake Suwa, the largest lake in Nagano, freezes over in winter, a rare phenomenon called omiwatari, or “God’s Crossing,” sometimes takes place. Omiwatari happens when the icy surface stretches due to the temperature differences between day and night, forming jagged ridges of ice that crack through the surface accompanied by a loud “ice thunder.”
Three ice ridges usually form on the frozen lake: two from the southeast part of the lake to the north, and one from the southwest to the east. Locals have long considered the omiwatari as traces of gods of the Suwa Taisha Shrines on both sides of the lake, specifically the trail of the god Takeminakata-no-kami of the Upper Suwa Shrine as he walks across the frozen lake to visit the goddess Yasakatome-no-kami of the Lower Shrine.
It is a breathtaking experience to witness rising slabs of jagged ice snaking out across the frozen lake, with the thunderous sounds accentuating the entire occurrence. However, the happening of omiwatari is getting increasingly rare due to the effects of climate change.
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