Why in the News?
The traditional ice ridge phenomenon called “God’s Crossing” (Miwatari) on Lake Suwa in Japan has failed to appear for the seventh consecutive year, highlighting long term warming trends linked to climate change.
Where is Lake Suwa?
- Located in Nagano Prefecture, Japan
- Associated with the Shinto shrine Yatsurugi Shrine
- One of Japan’s most well documented climatic sites
What is “God’s Crossing” (Miwatari)?
- Traditional Belief
- A raised ice ridge on the frozen lake surface.
- Believed to mark the path of a deity crossing the lake.
- Scientific Explanation
- Occurs when: Lake surface freezes completely and Temperatures remain below minus 10°C for several days.
- Ice expands and contracts due to temperature variation.
- Cracks form, refreeze, and push shards upward forming a ridge.
Climate Record Significance
- Continuous records date back to 1443.
- Shrine priests began systematic documentation from 1683.
- Includes:
- Date of full lake freeze
- Appearance of miwatari
- Ice thickness
- Temperature readings
Note: This makes Lake Suwa one of the longest continuous local climate records in the world.
Climate Change Indicator
- Phenomenon appeared almost every winter until the 1980s.
- Increasing winter temperatures have reduced full lake freezing.
- No appearance since 2018.
- Shows impact of rising minimum temperatures.
| [2022] Which one of the following lakes of West Africa has become dry and turned into a desert?
(a) Lake Victoria (b) Lake Faguibine (c) Lake Oguta (d) Lake Volta |
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