Avalanche Bulletin
更新日時: 2025/03/20 05:30
Hakuba
Alpine Fair
Treeline Fair
Below Treeline Fair
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
This is a day to be alert for unstable slabs that remain in certain terrains. Do not jump into large slopes out of the blue, but start the day on smaller slopes. Observe your surroundings carefully, look for traces of yesterday's wind and spot wind slab formations. Whatever type of instability is present, choosing a slope with a gentle slope is the most effective means of avalanche protection. Inexperienced persons should look for simple terrain with no "terrain traps" below the slope. For the more experienced, remember that a day that you skied one slope and had no problems is a day that does not guarantee safety on another slope. Always observe the slope with fresh eyes and consider if there are any elements that could increase instability. Snow is a good cold condition. If the slopes are less affected by the sun, you will enjoy excellent fresh snow. Have a good day.
Avalanche Problem
ウインドスラブ Wind slab
Be alert for wind slabs formed by yesterday's strong winds. Even if the surface layer has hardened over time, that does not mean it is safe. Underneath that slab may be hidden snow that has not yet gained sufficient strength. Be especially wary of terrain that is convex or unsupported, or the sides of a branch ridge.
ストームスラブ Storm slab
Watch out for unstable slabs that remain on steep slopes unaffected by yesterday's strong winds.
概要
Avalanche
Numerous avalanches of storm slabs of size 1-1.5 were reported yesterday (19th) in the below treeline. The upper snowpack is sensitive to human stimulation and a 20 m long shooting crack was also reported. A number of size 1 loose snow avalanches were also observed.
Snowpack
The depth of the new snow, brought about by two low-pressure transits in the last four days, followed by a short and strong winter pressure pattern, is around 60-80 cm near the treeline. And yesterday, strong northerly winds averaging over 20 m/s blew continuously throughout the day near the main ridge line. Currently, there are two concerns about the snowpack. The first is the extent of improvement in snow intensity due to the second low pressure system, which was sensitive to human stimulation yesterday, and the second is the condition of the wind slab formed by yesterday's strong winds.
Weather
The Japan Meteorological Agency is forecasting northerly winds, clear skies, and a daytime high of 8 °C (418 m elevation) for northern Nagano Prefecture. At the AMeDAS Hakuba (elevation 703 m), the temperature is -7.4 °C (as of 5:00 a.m.), with 4 cm of snow having fallen in the past 12 hours. At the main ridge (elevation 2,400 m), the temperature is -15 °C (as of 5:00) with northerly winds averaging about 2 m/s.
