Avalanche Bulletin
更新日時: 2025/02/10 05:30
Hakuba
Alpine Low Lack of information due to stormy weather
Treeline Fair Spatial variability of snowpack strength
Below Treeline Good
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Snowpack conditions in the mountains are shifting from high hazard conditions for the entire mountain to high hazard conditions only on certain slopes. At such times, we are more prone to errors in situational awareness. The instability of storm snow has not yet been fully resolved. While making prudent terrain choices and conservative decision making, gradually, check the snowpack conditions. Avoid steep slopes where the surface layer of snowpack as slab characteristics. Yesterday there were some avalanches triggered by a skier.
Avalanche Problem
ウインドスラブ Wind slab
The winds are subsiding, but we still need to be vigilant for wind slabs. A hard snow surface does not mean safety. Once slab formation is recognized, it is important to move to slopes with a slower angle.
ストームスラブ Storm slab
Low temperatures continue at higher elevations, and the instability of the stormy snow is slowly resolving. Be alert for unstable snow remaining on very steep slopes.
概要
Avalanche
Yesterday (9th), size 2 avalanches were reported on the northeast slopes below treeline and treeline. Both were caused by wind slabs and were triggered by skiers. Shooting cracks were also reported on the wind-slabbed slopes.
Snowpack
Below treeline, stormy snow is slowly sintering and consolidating. Where winds are present, the snow has an upside-down structure, and shooting cracks and avalanches have been observed. The condition of the boundary surface of the Melt-Freeze crust (buried on February 3), which is generally forming below 1,400 m elevation, is not good and continues to be of concern. The Melt-Freeze crust on the south face (buried January 25), which has formed to near the treeline, also has the potential to generate a large avalanche.
Weather
The Japan Meteorological Agency is forecasting northerly winds, cloudy skies, late evening snow, and daytime highs of 1 °C (418 m) for northern Nagano Prefecture. Snow, daytime high of 1 °C (418 m elevation) is forecast for northern Nagano. At Amedas Hakuba (elevation 703 m), the temperature is -4.7 °C (as of 5:00 pm), with no new snowfall in the past 12 hours. The Nagano District Meteorological Observatory is forecasting 30 cm of snowfall for northern Nagano Prefecture at 4:02 a.m. on February 10 in the 24-hour period ending at 6:00 a.m. on February 11. At the main ridge (elevation 2,400 m), the temperature is -16°C with northwest winds averaging 5 m/s and maxing out at 12-13 m/s.
