Avalanche Bulletin
更新日時: 2025/01/05 05:00
Hakuba
Alpine Fair
Treeline Low Degree of wind influence
Below Treeline Fair
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
It is a day when terrain selection is very important in four respects: 1. look for "wind effects" on the snow surface; 2. pay attention to changes in "likelihood of triggering" on steep south-facing slopes where solar radiation has a strong influence; 3. consider "terrain traps"; 4. The north-south gully of the Happo One and the Goryu-Tonomi One is itself a very large terrain trap. The safety zone is limited. 4. Pay attention to the behavior of the "other groups" above and below you. This is a day when the snow is well cooled by radiation and you can enjoy great powder snow, even at slightly slower slopes. Please manage your group with good communication with your companions and use the terrain to your advantage. Have a great day.
Avalanche Problem
ウインドスラブ Wind slab
The main ridge has been experiencing northwest to north winds averaging about 15 m/s since yesterday afternoon. This has increased the likelihood of wind slab formation in an upside-down structure on the downwind slopes from the alpine to the treeline. Also, please note that the steep southern slopes that will be affected by today's strong solar radiation will be more reactive due to the increased sintering of the upper snowopack.
ストームスラブ Storm slab
Watch for areas where recent snowfall has advanced sintering and formed slabs. Observe the effects of solar radiation during the day, especially on steep slopes facing south.
概要
Avalanche
Yesterday (4th), a size 1 loose snow avalanche or sluff was observed on a very steep slope below treeline. Data at higher elevations is not available.
Snowpack
Snowfall from January 2 to the morning of January 4 amounted to about 60 cm in the upper part of the below treeline. This new snow has accumulated below treeline with low cohesion and no wind effects, and small loose snow avalanches and sluffs were observed yesterday. On the steep south-facing slopes, Melt-Freeze crusts (formed on January 1) are buried under this new snow.
Weather
The Japan Meteorological Agency is forecasting southerly winds, sunny, occasionally cloudy, and a daytime high of 5 °C (418 m elevation) for northern Nagano Prefecture. At 703 m elevation (Hakuba), the temperature is -5.3 °C (as of 4:00 pm), with no new snowfall in the past 12 hours.
