Avalanche Bulletin
更新日時: 2023/02/01 05:30
Hakuba
Alpine Fair
Treeline Good
Below Treeline Good
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Be careful of unstable snow remaining on extreme terrain features. On the steep south-facing slopes, crusts have formed due to yesterday's sun exposure, so please be careful when skiing. On the north-to-east-facing slopes, there is a dry and supportive powder with a good riding feel. Falls in the mountains can cause all kinds of problems, so please keep your speed under control and enjoy the JAPOW. Creeks in the forest have filled in well, but not as well as in previous years. Imagine that there are holes in the gully bottoms, which are hidden by the recent snowfall, and choose safe routes. Have a nice day.
Avalanche Problem
ウインドスラブ Wind slab
Note slabs formed on isolated extreme terrain shapes
持続型スラブ Persistent slab
The tenperature gradient has dissipated and rounding has progressed up to 2,300 m elevation; the rainfall on January 14 affected the area up to 2,500 m elevation. Currently, there is a lack of observational information at Alpine, and there is a high degree of uncertainty.
概要
Avalanche
Yesterday (January 31), several size 2 slab avalanches were observed on the eastern slopes of the Below Treeline, most likely occurring within the past 24 hours. In the alpine area, several size 2-3 slab avalanches were observed on the northeast-to-southeast slopes.
Snowpack
The upper layer of snowpack (30-50 cm) from the January 30 snowfall is settling due to yesterday's fine weather, and crusts are forming on the south-facing slopes at lower elevations than Treeline due to solar radiation. The middle layer of snowpack is sintering, becoming denser and stronger, and the "faceted snow" that formed on top of the Melt-Freeze crust formed by the rainfall on January 14 has lost its tenperature gradient and is becoming more rounding. Regarding the avalanche that occurred on January 29 at Tenguhara, a fracture line investigation was conducted yesterday, and it was confirmed that it was a thin Melt-Freeze crust formed by solar radiation on January 16 and faceted snow that formed on top of it. It was observed that the tenperature gradient in this weak layer has also dissipated and that the snow crystals are becoming rounding.
Weather
The Japan Meteorological Agency is forecasting southerly winds, clear skies, cloudy from midday, snow in places, and a maximum temperature of 7°C (418 m elevation) for northern Nagano Prefecture. At the valley of Hakuba (elevation 703m), the temperature is -9.9°C (as of 5 am), with no new snowfall in the past 12 hours.
