Avalanche Bulletin
更新日時: 2025/02/22 05:30
Hakuba
Alpine Low Lack of information due to stormy weather
Treeline Fair
Below Treeline Good
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Aside from a few lingering concerns (crusts buried February 17), the instability of the mountain snowpack is slowly and steadily resolving. Reaction to human stimulation has slowed, but we still need to be very vigilant on isolated, very steep slopes. This stormy weather has brought 80-100 cm of snowfall, hiding glide cracks that have formed previously. Remember that glide cracks may be hidden by fresh snow at the turn of the slope. Even if you feel that the snowpack is stable, observe the principle behaviors of skiing one person at a time and staying in a safe place. This will minimize accidents. Have a good weekend while maintaining good communication with your fellow skiers.
Avalanche Problem
ウインドスラブ Wind slab
Watch out for unstable slabs that remain in isolated terrain. Consider the effects of incoming solar radiation.
ストームスラブ Storm slab
Be on the lookout for Melt-Freeze crusts (buried February 17) where they are shallowly buried. Information is scarce and uncertain at the treeline and alpine. Also, otherwise, watch for unstable slabs remaining in very steep, isolated terrain.
概要
Avalanche
Yesterday (20th), a size 1 slab avalanche caused by a ski cut was reported on a very steep slope near the treeline. Several size 1 loose snow avalanches due to ski cuts were also reported. The alpine area has not been reported due to poor visibility.
Snowpack
In the treeline and below treeline, snow from the stormy weather that began on February 17 has been observed to be steadily sintering and consolidating. The upper layer of the snowpack is generally right-side up structure, except where winds are present. The interface between the Melt-Freeze crust (buried on February 17) and the storm snow has been continuously investigated, and it has been observed that below treeline, the tenperature gradient has also generally dissipated. However, high elevations are not yet sufficiently reassuring, so ongoing surveys will be conducted.
Weather
The Japan Meteorological Agency is forecasting northerly winds, cloudy, with occasional snow, and a daytime high of 2 °C (418 m) for northern Nagano Prefecture. At Amedas Hakuba (703 m), the temperature is -7.9 °C (5:00 a.m.), and 1 cm of snow has fallen in the past 12 hours. At the main ridge (elevation 2,400 m), the temperature is -17.5°C (5:00 a.m.), with northerly winds averaging 5 m/s and a maximum of 7 m/s at the moment. The Nagano District Meteorological Observatory forecast 25 cm of snowfall for northern Nagano Prefecture at 4:34 a.m. on February 22 in the 24-hour period ending at 6:00 a.m. on February 23.
