30 years of satellite ocean data can predict Japan's snowfall. No meteorology degree required.
How much powder dumps on your favourite Japanese ski resort is surprisingly predictable — using ocean temperatures near the equator. Here's the three-step mechanism.
Every few years, sea surface temperatures in the central Pacific drop below normal. Scientists call this La Niña. It sounds exotic, but its effects reach all the way to Japan.
La Niña shifts global atmospheric circulation, strengthening the Siberian High. This sends frigid, dry air screaming across the Sea of Japan. As it crosses the warm water (heated by the Tsushima Current), it hoovers up enormous amounts of moisture.
That moisture-loaded air slams into Japan's mountain spine and gets forced upward. Instant snow clouds. The result: some of the deepest, lightest powder on Earth — the legendary JAPOW. Myoko, Nozawa, Madarao, and Kagura get absolutely buried.
The ONI (Oceanic Niño Index) measures how warm or cool the tropical Pacific is vs. normal. Positive = warm (El Niño). Negative = cool (La Niña). This single number explains more about Japan's winter snow than any other variable.
Peak snow depth at Tokamachi (Niigata Prefecture, gateway to Myoko/Madarao) tells the story.
Average peak snow depth (30 yrs)
Epic: 2006 345cm · 2012 345cm · 2018 320cm
Average peak snow depth (30 yrs)
Disappointing: 2016 100cm · 2024 92cm
Blue = La Niña. Red = El Niño. Grey = neutral. Taller bars = more snow. See the pattern?
We'll publish our seasonal prediction once ENSO forecasts stabilise in early autumn. Bookmark this page — it's the first place you'll know whether to book that JAPOW trip.
Niseko, Myoko, Hakuba, Nozawa — how does ENSO affect each resort differently?
Ranked by La Niña snow response.
8 resorts · ONI correlation · seasonal snowfall ranges