Avalanche Bulletin
更新日時: 2025/03/05 06:00
Hakuba
Alpine Fair
Treeline Fair
Below Treeline Fair
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
This is a day of avalanche danger of different types depending on elevation zones. At higher elevations, be on the lookout for slabs formed by the most recent snowfall. The passage of a low pressure system was accompanied by snow with large grain size. Therefore, consider that an avalanche can be triggered by a single person on steep slopes where slabs have formed due to wind redistribution of fresh snow. This type of storm slab, although soft, tends to be more responsive to human stimulation. In addition, the fresh snow makes it difficult to see glide cracks, so be careful at the turn of the slope. On the other hand, at lower elevations, be on the lookout for wet snow avalanches.
Avalanche Problem
ストームスラブ Storm slab
Watch out for steep slopes where the wind has increased the amount of fresh snow accumulation. Assess below treeline at higher elevations where it has not been raining.
面発生湿雪雪崩 Wet slab
New snow on the Melt-Freeze crust will be wet from this morning's rainfall, increasing the risk of a surface-generated wet avalanche. Be vigilant in lower elevation areas.
全層雪崩 Glide slab
There is a risk of glide avalanche at lower elevations where it is raining. Stay away from slopes that already have glide cracks. Be alert for collapsing snow blocks that remain on cliff-like terrain.
概要
Avalanche
Yesterday (4th), a size 1 storm slab avalanche was reported on the northeast slope of the treeline. This avalanche was caused by a ski cut. In addition, a wet slab avalanche (size 3-3.5), which appears to have occurred during rainfall on March 3, was observed on the south face of Happo One (around 1,400 m elevation). Several glide avalanches (size 1-2) have been observed below treeline.
Snowpack
Snowfall since March 3 led to snowfall by a south coast low pressure system around 14:00 on March 4, and by this morning it appears to have reached 20-30 cm in the upper part of the below treeline. Underneath this new snow is a very hard Melt-Freeze crust. At lower elevations (below 800 m), rain has been falling since this morning. At higher elevations, it is necessary to check for vulnerabilities within the new snow or bonding between the new and old snow. At lower elevations, we need to be on the lookout for avalanches of wet snow.
Weather
The Japan Meteorological Agency is forecasting winds from the south, slightly stronger, then from the north, cloudy, with occasional rain or snow until late afternoon, and a daytime high of 9 °C (418 m elevation) for northern Nagano Prefecture. At Amedas Hakuba (elevation 703 m), the temperature is -1.1 °C (as of 6:00 am), with 9 cm of snow having fallen in the past 12 hours. At the main ridge (elevation 2,400 m), the temperature is -3.4 °C (as of 5:00) with northwest winds averaging about 10 m/s.
