Avalanche Bulletin
更新日時: 2024/03/08 05:00
Hakuba
Alpine Low
Treeline Low
Below Treeline Fair Be aware of rising temperatures during the day and the effects of solar radiation
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
From a decision-making perspective, it is a very tricky day. The weather is improving, the winds are less severe, and the snow looks good, so it is tempting to get into the big slopes. However, on certain treeline and alpine slopes, persistent slabs lurk that can trigger large avalanches. Even if the potential for triggering is not very high, once they occur, they can be large in magnitude. Because the weak layer that triggers the avalanche is in the middle of the snowpack, it is not possible to take safety measures with ski cuts, as is the case with storm slabs. Furthermore, weak layer formation has been observed to vary from place to place. All we can do is make safe terrain choices. This season's avalanche fatalities are all experienced climbers or riders who seem to be avid readers of this avalanche bulletin. Remember the decades old golden rule: "Question is Stability, Answer is Terrain". Have a good day.
Avalanche Problem
ウインドスラブ Wind slab
Winds have decreased since yesterday afternoon (7th). Note where time-lapsed slabs remain in terrain pockets.
ストームスラブ Storm slab
Watch out for slabs that form on very steep slopes or where the terrain is not conducive to supporting a snowpack.
持続型スラブ Persistent slab
It is suspected that the avalanche observed yesterday was a persistent slab. This type of avalanche is triggered from areas where the snowpack is thin. Be on the lookout for areas near exposed rocks or where the overall snowpack is thin due to wind. It is necessary to choose low angles slopes and avoid areas where the terrain has features that are difficult to support the snowpack, such as isolated terrains or convex shapes.
概要
Avalanche
Yesterday (6th), a size 2 slab avalanche was observed on the southeast face of Happo One, near 2,000 m elevation, that is believed to have occurred within the past 24 hours. This avalanche is suspected to be a persistent slab.
Snowpack
The stormy snow is slowly sintering, leaving unstable slabs at isolated terrain. Near the treeline, there has been a recent snowfall of about 40 cm, so it is possible that the weight of the snow has awakened persistent slabs. The avalanche observed at Happo One has a different meaning than the avalanches often seen immediately after stormy weather, and is of great concern to the team involved in avalanche bulletin.
Weather
The Japan Meteorological Agency is forecasting northerly winds, cloudy and occasionally sunny with a daytime high of 8 °C for northern Nagano Prefecture. At 703 m elevation (Hakuba), the temperature is -3.1 °C (as of 5:00 a.m.), with no new snowfall in the past 12 hours.
