As we approach the 2024/25 snow season in Japan, winter sports enthusiasts and residents alike are eagerly anticipating the weather forecast. This year, the focus is on La Niña, a climate phenomenon known for its impact on global weather patterns, including Japan’s snowfall. This article will explain what La Niña is, the current forecast, and what it could mean for the 2024/25 ski season.
What is La Niña?
La Niña is a large-scale ocean-atmosphere climate phenomenon characterized by cooler-than-average sea surface temperatures in the central and east-central equatorial Pacific. As part of the broader El Niño-Southern Oscillation (ENSO) cycle, La Niña represents the cool phase, leading to different weather patterns globally. For Japan, La Niña typically brings colder and wetter conditions, contributing to heavier snowfall.
Two key criteria must be met for a La Niña event to be declared:
- Sea Surface Temperature Anomaly: The average sea surface temperatures in the Niño-3.4 region of the equatorial Pacific Ocean must be at least 0.5°C cooler than average for the preceding month.
- Persistence: This temperature anomaly must persist or be expected to persist for five consecutive overlapping three-month periods.
Forecast for the 2024/25 Snow Season
Confidence is growing that La Niña conditions will emerge during the 2024/25 winter season. As of August 2024, ENSO-neutral conditions have prevailed, but long-range forecasts indicate a higher-than-average probability of La Niña developing in late fall. The weekly Nino-3.4 region index anomaly, which reflects sea surface temperatures, has dropped from 1.8°C during the 2023/24 winter season to -0.1°C as of September 9, 2024. This shift mirrors a similar change from El Niño to La Niña seen in the summer of 2016.
According to the Japan Meteorological Agency, there is a high likelihood (around 60%) that La Niña conditions will develop by fall 2024 and persist through the winter. If these conditions hold, Japan could experience a colder and snowier winter, especially in regions such as North Nagano and Myoko Kogen. This is excellent news for winter sports enthusiasts, as La Niña winters historically bring abundant snowfall, leading to fantastic ski conditions.
Historical Impact of La Niña on Japan’s Snowfall
Historically, La Niña has significantly influenced Japan’s winter weather. During La Niña years, the Siberian High, a large area of high atmospheric pressure over Siberia, tends to strengthen. This intensified pressure system allows cold air to flow more easily into Japan. As this cold air passes over the warmer waters surrounding Japan, it picks up moisture, resulting in increased snowfall when it reaches mountainous regions.
For example, the La Niña event of 2010/11 brought record snowfall to many parts of Japan, with ski resorts in Hokkaido and the Japanese Alps reporting some of their best snow conditions in years. Similarly, the 2020/21 La Niña winter delivered exceptional snowfall in the Madarao and Myoko Kogen areas -but just above average in the Northern Alps region, thrilling winter sports enthusiasts but creating challenges for insurance companies that faced numerous claims to repair structures damaged by the weight of the heavy snow.
At La Colina Retreat in 2021, the roofed passage between the two buildings collapsed under the weight of snow, and we had to hire the services of industrial-size snow blowers to clear access routes and the parking lot.
Preparing for the Season
With a high likelihood of La Niña this winter, it’s essential for residents and visitors to prepare accordingly. Proper winter gear, staying updated with weather forecasts, and planning travel with potential snow disruptions in mind can help mitigate the challenges posed by heavier snowfall.
Conclusion
The 2024/25 snow season in Japan is shaping up to be an exciting one. The anticipated La Niña conditions promise a winter filled with abundant snowfall, creating ideal conditions for skiing and snowboarding. However, it also serves as a reminder of the broader impacts of such climate phenomena and the importance of being prepared.
Are you ready for the upcoming snowy season?