Avalanche Bulletin
更新日時: 2025/03/21 05:30
Hakuba
Alpine Fair
Treeline Fair
Below Treeline Good
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
In alpine, be alert for newly formed wind slabs. Previous stormy snow is resolving its instability, but caution is still advised in characteristic terrain pockets that are more prone to avalanche triggering, such as very steep and unsupported terrain. Also, pay close attention to the snow conditions on the snow surface today, which will change dramatically as a result of the rising temperatures and solar radiation during the day. Wet snow is very heavy and easily scoots underfoot. Any "terrain traps" downslope can have serious consequences. It will be a hot day. Bring sunscreen and plenty of water and have a good day.
Avalanche Problem
ウインドスラブ Wind slab
The wind was light during the day yesterday (20th), but very strong winds have been blowing on the main ridge since this morning. Watch out for newly formed wind slabs.
ストームスラブ Storm slab
Avalanches can still occur in very steep, unsupported, multi-element terrain pockets.
点発生湿雪雪崩 Wet Loose snow
Rating is as of morning. Notice the decrease in snow intensity on steep slopes in strong daylight.
概要
Avalanche
Yesterday (20th), several size 1 storm slab avalanches were reported near the treeline. All were human-triggered on very steep slopes. A size 1 loose snow avalanche was also observed on a very steep south slope with exposed rock.
Snowpack
Yesterday's sunny slopes have formed crusts 3-5 cm thick on the snow surface. Near the treeline, the snow below the crust is still dry but very hard to ski on. In addition, the upper layer of snow in this elevation zone has snow from the last two low-pressure systems and is not yet completely sintering. There is also a thin Melt-Freeze crust at shallow depths on the south side of the below treeline, and small slab avalanches have occurred at the boundary of this crust.
Weather
The Japan Meteorological Agency is forecasting a southerly wind, clear skies, and a daytime high of 15 °C (418 m elevation) for northern Nagano Prefecture. At Ameda Hakuba (elevation 703 m), the temperature is -4.3 °C (as of 5:00 a.m.), with no precipitation in the past 24 hours. At the main ridge (elevation 2,400 m), -9 °C (as of 5:00), with northerly winds averaging 10 m/s and a maximum instantaneous wind speed of 26 m/s.
