Avalanche Bulletin
更新日時: 2025/03/06 05:30
Hakuba
Alpine Low Uncertainty related to snowfall amounts
Treeline Low
Below Treeline Good
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
At higher elevations, watch for wind slabs if there is any dry snow remaining. Winds have been picking up since early today, and new slabs are characterized by a tendency to crack. Also, in areas where the snow surface was wet yesterday, it has frozen hard due to the cold temperatures, so be on the lookout for slips and falls. On the other hand, at very low elevations, positive temperatures are continuing. Be on the lookout for glide avalanches and snow block collapses. Do not stay below slopes with glide cracks.
Avalanche Problem
ウインドスラブ Wind slab
Wind slabs are expected to form due to northerly winds that have strengthened since dawn at higher elevations where there was no rain or sleet yesterday and the snow surface was not wet.
全層雪崩 Glide slab
At the base of the mountain, positive temperatures have continued since yesterday. Stay away from slopes with glide cracks. Watch for collapsing snow blocks on cliff-like extreme terrain.
概要
Avalanche
Yesterday (5th), a size 1 wet slab avalanches were observed in the below treeline. This avalanche was human-caused by a ski cut. In addition, the previous day's snowfall was wetted by high temperatures and rainfall, and numerous snowballs were observed. Due to the stormy weather, no information was received at higher elevations.
Snowpack
Yesterday, the temperature was higher than forecasted, reaching almost zero degrees even near the main ridge. Snow or sleet fell in the alpine areas, but rain fell at lower elevations. Then, a low pressure system moved out of the south coast to the east of Japan, creating a winter pressure pattern, and cold air began to move in yesterday evening. As a result, the wet snow surface is frozen hard. At the foot of the mountain, at this time, positive temperatures have continued since yesterday, so there is a risk of glide avalanche.
Weather
The JMA is forecasting northerly winds, cloudy skies, night, snow, and a daytime high of 5 °C (418 m elevation) for northern Nagano Prefecture. At AMeDAS Hakuba (elevation 703 m), the temperature is 0.5 °C (as of 5:00 am), and no new snow has fallen in the past 12 hours. At the main ridge (elevation 2,400 m), the temperature is -10 °C (as of 5:00), with northerly winds averaging 14 m/s and a maximum instantaneous wind speed of about 18 m/s. At 4:02 a.m. on March 6, the Nagano Prefectural Meteorological Observatory forecast 20 cm of snowfall for northern Nagano Prefecture in the next 24 hours until 6:00 a.m. on March 7.
