Japan’s Lake Suwa fails to freeze fully, halting the sacred “God’s Crossing” ritual, as scientists and priests warn rising temperatures are erasing centuries-old traditions and signaling accelerating climate change impacts.
Before dawn on a bitter winter morning, a Shinto priest and his followers gathered at Lake Suwa, hoping nature had not denied them a rare spiritual moment that is slipping away with time.
The group, mostly men in their sixties, came to witness “miwatari” or “God’s Crossing”, a centuries-old phenomenon in which a ridge forms across the frozen lake. According to local belief, it marks the path of a deity crossing the ice to visit his goddess wife.
But in recent years, the sacred event has become increasingly elusive.
Led by priest Kiyoshi Miyasaka of Yatsurugi Shrine, the annual vigil began on January 5. One man carried a weathered flag, another held a large axe, and all wore jackets bearing the shrine’s crest as they approached the lake with cautious optimism.
“This is the start of the decisive 30 days,” Miyasaka told the group.
That optimism quickly faded. As they reached the shoreline, the water appeared dark and unsettled in the pre-dawn light.
“How pitiful,” Miyasaka said quietly, lowering a thermometer into the lake.
The disappointment reflects a broader shift. The “God’s Crossing” has not appeared since 2018, marking a seven-year absence at the time of the gathering, and now extending to eight years, tying the longest recorded “godless” period from the early 16th century.
However, climate researcher Takehiko Mikami questions the reliability of records from that era and believes the current stretch may be the longest on record.
For centuries, priests at Yatsurugi Shrine have documented when the lake fully froze and when the crossing appeared. Continuous records date back to 1443, with shrine priests formally maintaining them since 1683. In modern times, they have added temperature readings and ice thickness measurements.
Naoko Hasegawa, a geographer at Ochanomizu University in Tokyo, described the archive as unparalleled.
“The chronicle shows data taken at a single location over hundreds of years, and thanks to it, we can now see what the climate was like centuries ago,” she said. “We find no other meteorological archive comparable to it.”
Researchers worldwide consider the records a valuable resource for studying climate history.
Both scientists and local believers now point to climate change as the reason behind the disappearance of the phenomenon.
“We are seeing the signs of climate change in many places of the world, and Lake Suwa is no exception,” Miyasaka said. “Nature doesn’t lie.”
Scientifically, the crossing forms only when the lake freezes completely, which requires several consecutive days with temperatures below minus 10 degrees Celsius. As temperatures fluctuate between night and day, the ice contracts and expands, creating cracks. These cracks fill with newly frozen water, forming jagged ridges that sometimes rise to eye level and produce a deep roaring sound.
Mikami recalls witnessing the phenomenon in 1998.
“The surface froze completely to about 15 centimetres thick. We could walk all the way across the lake to the other shore,” said the professor emeritus at Tokyo Metropolitan University.
His research shows the crossing occurred almost every winter until the 1980s. Since then, morning temperatures have often failed to drop low enough for a full freeze.
“This is a warning from nature,” Mikami said.
This winter briefly raised hopes. On January 26, after weeks of freezing morning observations, the group recorded a full freeze. They celebrated as a block of ice was cut and presented to Miyasaka for measurement.
But the ice melted within days before any crossing could form.
By February 4, Miyasaka declared the lake an “open sea”, or “ake no umi”, indicating there was little chance of the phenomenon appearing before spring.
Full freezes, once a seasonal certainty, have now become rare.
Over more than four decades in his role, Miyasaka has conducted the traditional Shinto ritual on the ice just 11 times.
Despite the growing uncertainty, he remains committed to preserving the tradition and its record.
“We will report it was a season of ‘open sea’, passing on the message to people 100 years from now,” he said.
For Mikami, the prolonged absence carries a stark message.
“Global warming is accelerating,” he said. “If the trend continues, I am afraid we will never see the miwatari phenomenon again.”
This article is republished from AFP.
