Avalanche Bulletin
更新日時: 2025/01/20 05:30
Hakuba
Alpine Fair
Treeline Fair
Below Treeline Good Degree of temperature increase
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Generally safe avalanche conditions. Watch for locally unstable snow remaining in isolated terrain. Even a size 1 avalanche can be serious if there is a "terrain trap" below it, so be sure to check the terrain. Even on days when the snowpack is stable, please take some risk-reducing actions in accordance with the general rules of conduct. This is because such behavior will minimize damage in the event of an emergency. Habits are not formed in a day. There are many glide cracks. Please pay attention to changes in slope.
Avalanche Problem
ウインドスラブ Wind slab
Beware of partially unstable snow forming on extreme terrain shapes.
全層雪崩 Glide slab
Note the very low elevation and extreme terrain with glide cracks already in place.
概要
Avalanche
Yesterday (19th), a very small wet loose snow avalanche on a very steep slope in the lower bellow treeline and a size 1 dry loose avalanche on a very steep slope on the north side at higher elevation were observed.
Snowpack
Two days of clear skies and yesterday's high temperature (703 m at the base of the mountain, 6.4 °C, at 2 pm) caused three things to happen. First, on the steep south-facing slopes, where the effects of the solar radiation and high temperatures were stronger, the snow melted on the snow surface during the day and crusts formed at night; second, on the north-facing, windless slopes, radiation caused heat to escape and the snow dried out and became lighter; and third, the generally warm air promoted sintering and settling of the snow on the upper snowpack. Where the first two factors were strong, two types of avalanches were observed yesterday.
Weather
A south coast low pressure system with warm air is moving to the northeast. The Japan Meteorological Agency is forecasting southerly winds, later northerly winds, cloudy, sometimes sunny, with a daytime high of 9 °C (418 m elevation) for northern Nagano Prefecture. At Amedas Hakuba (elevation 703 m), the temperature is -5.5 °C (as of 5:00), with no new snowfall in the past 12 hours. Alpine (elevation 2,400 m) has a temperature of -6.8 °C (as of 5:00) with an average wind speed of 3 m/s.
