Avalanche Bulletin
更新日時: 2025/02/06 05:30
Hakuba
Alpine Fair
Treeline Fair
Below Treeline Good
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Very dangerous avalanche conditions. Even if the snowfall has weakened, the greatest caution should be exercised on wind slabs formed by winds that have been particularly strong since yesterday afternoon. Even if you are in the forest, be aware of the avalanche tracks and start zones above you in the forest. In the steep terrain on both sides of the Happo and Tohomi ridges, this is the day when avalanches of the size (SIZE 3) that flow downstream with a difference in elevation of 1,000 m, where the avalanche reaches the valley bottom, can occur. Don't be lulled into a false sense of safety just because you are at a lower elevation. This is a good day for inexperienced groups to enjoy powder snow in the ski resort. When doing so, buddy up with a fellow skier and respect the run area. It is not only for your safety, but also for the safety of other guests.
Avalanche Problem
ウインドスラブ Wind slab
On the main ridge, there is a blast wind with an instantaneous maximum wind speed approaching 40 m/s. This wind is traveling through and around the terrain and down to the lower elevations, forming wind slabs in various locations.
ストームスラブ Storm slab
Snowfall is repeatedly strong and weak, and there is a weak layer within the fresh snow that causes it. In steep terrain, it is easy to see how they can be easily triggered by human irritation. Also, because fresh snow is deep and soft, even a small avalanche can be fatal if swept into a small terrain depression, resulting in a deep burial. Maximum attention to terrain is required.
概要
Avalanche
Yesterday (5th), there were many reports of avalanches below treeline. The size was size 1-2 and the type was storm slab or loose snow avalanche, all caused by ski cuts or other human stimuli. All of these were caused by intensified snowfall.
Snowpack
The stormy snow that began on February 3 is 60-80 cm below treeline as of yesterday (5th). Here is a listing of 20-30 cm of new snow since last night. As of yesterday, the bonding between the Melt-Freeze crusts at lower elevations (buried on February 3) and the new snow was poor and sensitive to human stimulation. The boundary surface of the Melt-Freeze crust (buried January 25), which is located at a deeper elevation, remains uncertain with no information available.
Weather
The Japan Meteorological Agency is forecasting southerly winds, snow, cloudy from midday, and a daytime high of 2 °C (418 m elevation) for northern Nagano Prefecture. At Amedas Hakuba (elevation 703 m), the temperature is -6.7 °C (as of 5:00 pm), and 16 cm of snow has fallen in the past 12 hours. The Nagano District Meteorological Observatory forecast 20 cm of snowfall for northern Nagano Prefecture at 4:16 a.m. on February 6 in the 24-hour period ending at 6:00 a.m. on February 7. At the main ridge line (elevation 2,400 m), the temperature is -18°C, with northerly winds averaging 17 m/s and maximum wind speeds of 30 m/s or higher.
