Avalanche Bulletin
更新日時: 2025/02/04 05:30
Hakuba
Alpine Fair
Treeline Fair
Below Treeline Fair
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
A very clear pattern of instability is emerging. Today, avalanche danger will increase rapidly as snowfall increases. Avalanches are possible in steep, open areas, even in forested areas. As has been widely reported, weather conditions will be distinctly worse. Inexperienced groups are advised to ski in the ski resort.
Avalanche Problem
ストームスラブ Storm slab
As snowfall increases, both the size of the avalanche and its triggering sensitivity increase rapidly. Where fresh snow on the surface has the characteristics of a slab, it is sensitive. Very careful terrain selection is necessary.
概要
Avalanche
Yesterday (the 3rd), a size 1-1.5 slab avalanche was observed on very steep terrain at the treeline. In addition, size 1 dry loose snow avalanches of size 1, triggered by ski cuts, were observed in all directions in the treeline and below treeline.
Snowpack
Yesterday, a low pressure system moving northeastward over the Sea of Japan brought in warmer air, resulting in wet and heavily settled snow surfaces below 1,300 m elevation. In addition, about 5 cm of low cohesion snow fell, which was sensitive to ski cuts and caused small loose snow avalanches. When this snow is buried by future storm snow, it will become an easily recognizable weak layer that will generate avalanches.
Weather
The Japan Meteorological Agency is forecasting northerly winds, cloudy skies, occasional snow, and a daytime high of 3 °C (418 m elevation) for northern Nagano Prefecture. The Nagano District Meteorological Observatory is forecasting 40 cm of snowfall for northern Nagano at 3:16 a.m. on the 4th in the 24-hour period ending at 6:00 a.m. on the 5th. At 703 m elevation (Hakuba), the temperature is -3.4 °C (as of 5:00 a.m.), and no new snowfall has been recorded in the past 12 hours. At the main ridge (elevation 2,400 m), the temperature is -15 °C with an average wind from the northwest of 15 m/s.
