Avalanche Bulletin
更新日時: 2024/02/09 05:30
Hakuba
Alpine Fair
Treeline Fair
Below Treeline Good Note the effects of elevated temperature and solar radiation
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Instability in the mountain snowpack is slowly dissipating. Watch for unstable snow remaining in terrain pockets. Consider whether there are "terrain traps" lower down the slope where even a small avalanche can have deadly consequences. Even if you feel that snow conditions are good, remember to manage your group using safe terrain. Have a good day.
Avalanche Problem
ウインドスラブ Wind slab
Weak winds of less than 10 m/s are continuing on the main ridge. Watch for snow movement where winds converge and slabs forming in terrain pockets. The wind direction is shifting to the southwest, so consider that as well.
ストームスラブ Storm slab
Watch out for areas with very steep slopes and extreme shapes.
概要
Avalanche
Yesterday (8th), a size 1 loose snow avalanche was observed on a steep slope at a higher elevation and unaffected by solar radiation and wind. An older size 2 slab avalanche was also reported.
Snowpack
The same trend has continued over the past few days: the low-pressure snow that fell on the 5th has become old snow and is slowly sintering. On the southern slopes, thin crusts have formed on top of this old snow, either due to sunny slopes or warming. In the past few days, there has been weak snowfall due to the cold air above, which has been placed on top of the crusts or old snow. There is a hard Melt-Freeze layer in the middle of the snowpack, and the low-pressure snow is on top of it. We have not found any bad information on the strength of this boundary, but we are keeping a close eye on it because the layer of low-pressure snow still has the potential to slab avalanche if it rapidly increases in hardness and takes on a stiff slab character.
Weather
Today, the area will be covered by high pressure, but is expected to be affected by a trough and cold air. The Japan Meteorological Agency is forecasting northerly winds, cloudy, sometimes sunny, and a daytime high of 6 °C for northern Nagano Prefecture. At 703 m elevation, the temperature is -4.7 °C (as of 5:00 a.m.), with no new snowfall in the past 12 hours.
