Avalanche Bulletin
更新日時: 2025/02/15 05:30
Hakuba
Alpine Fair
Treeline Fair
Below Treeline Good
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
This is a day when terrain selection is extremely important on two fronts. First, storm instability (windslab/stormslab) still remains in specific terrain features. Second, the mountain is likely to be crowded with skiers, so please be mindful of your relationship with other groups and make good use of safe terrain. Do not attempt to ski cut at the top when there are other groups below. Hard snow surfaces are exposed on wind-controlled ridges. Be careful of slipping and falling. There is excellent powder snow in the trees unaffected by the wind. Have a good weekend.
Avalanche Problem
ウインドスラブ Wind slab
Winds in the mountains are subsiding, but remain vigilant for wind slabs. Stabilization of wind slabs varies from place to place. Also, expect destabilization on steep slopes exposed to strong daytime solar radiation, due to the effects of rising temperatures. Gentle slope angles and avoidance of isolated terrain are effective.
ストームスラブ Storm slab
In very steep, isolated terrain, for example, still consider that avalanches can be triggered by human stimulation. Avoid localities that have multiple features that are prone to triggering, such as convexity, lack of underpinning, etc.
概要
Avalanche
Yesterday (14th), as visibility gradually improved, numerous avalanches were observed. Slab avalanches up to size 1-3 were reported on east to south facing slopes in all elevations from below treeline to alpine. These will be wind slabs formed by strong winds over the past few days. Many of the larger size avalanches occurred during stormy weather, while the smaller size avalanches occurred on the same day.
Snowpack
Weak rainfall on the night of February 12 wetted the snowpack up to around 1,600 m elevation, creating a thin Melt-Freeze crust. Tenperature gradients and faceting have been observed at some of these boundaries. It was also confirmed yesterday that the lower part of this crust has graupel with very low cohesion and is not yet fully sintering. In addition, the new snow the past three days has been affected by extremely strong northerly winds, causing wind slabs to form in various locations.
Weather
The Japan Meteorological Agency is forecasting winds from the south, later from the north, clear, night, cloudy, with a daytime high of 9 °C (418 m elevation) for northern Nagano. At AMeDAS Hakuba (elevation 703 m), the temperature is -5.9 °C (as of 5:00 pm), with no new snowfall in the past 12 hours. On the main ridge (elevation 2,400 m), the temperature is -9 °C, with northerly winds averaging 10 m/s and max. instantaneous 12-13 m/s.
