Avalanche Bulletin
更新日時: 2025/02/18 05:30
Hakuba
Alpine Fair
Treeline Fair
Below Treeline Fair
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Very dangerous avalanche conditions. Even if you are in the forest, pay maximum attention to the start zones where wind-driven snow has accumulated. This is a day for using terrain with a large safety margin and conservative decision-making. Even a size 1 avalanche can be deadly if swept through the forest, striking trees. For inexperienced skiers, powder ridings in the ski resorts are recommended. When skiing in powder snow areas, use the buddy system with a companion.
Avalanche Problem
ストームスラブ Storm slab
Temperatures are dropping with the inflow of cold air. The instability that was clearly observed yesterday continues today, and the increased snow cover should be considered a potential situation for large avalanches.
概要
Avalanche
Many size 1 storm slabs were observed yesterday (17th) in the below treeline. The bed surfaces are Melt-Freeze crusts of old snow. Shooting cracks of 5-10 m were also reported. Due to stormy weather, no information is available at higher elevations.
Snowpack
Snowfall began around 8:00 AM yesterday morning (17th). Due to a small low pressure system passing to the north of Nagano Prefecture, there was no wind and the snowfall was caused by high temperatures. Later, when the low pressure system passed to the east, it turned into a snow storm. Heavy winds caused some lift operations to be suspended. Below treeline, 25-30 cm of snow fell during the day, resulting in easy avalanches on ski cuts. Below treeline, snowfall since yesterday is 50-60 cm, affected by strong northerly winds.
Weather
The JMA is forecasting northerly winds, snow, morning to early afternoon, cloudy, and daytime highs of 3 °C (418 m elevation) for northern Nagano Prefecture. At AMeDAS Hakuba (elevation 703 m), the temperature is -6.7 °C (as of 5:00 am), and the snow depth has increased by 17 cm in the past 24 hours. At the main ridge (elevation 2,400 m), the temperature is -19°C (as of 5:00) with northerly winds averaging nearly 20 m/s. The Nagano Prefectural Meteorological Observatory forecast 40 cm of snowfall for northern Nagano Prefecture at 4:14 a.m. on February 18 in the 24-hour period ending at 6:00 a.m. on February 19.
