Avalanche Bulletin
更新日時: 2025/03/07 07:00
Niseko Yotei Yoichi Shiribeshi
Alpine Fair Limited alpine observations
Treeline Good Continued snowfall will cause the hazard to increase through the day.
Below Treeline Good Continued snowfall will cause the hazard to increase through the day.
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Storm totals in the North of the region have reached the threshold to cause larger avalanches and there are notable instabilities within the storm snow. Monitor these instabilities carefully and take note of areas where the new snow overlies a crust. Bonds are improving particularly on polar aspects where the crusts are less defined and don`t exist at higher elevations. Continued patience is needed while the new snow bonds to the old surfaces.
Avalanche Problem
ウインドスラブ Wind slab
Moderate NW winds at treeline and above have re-distributed the storm snow to leeward aspects.
ストームスラブ Storm slab
Mild temperatures at lower elevations are promoting storm slab formation over density inversions that exist above the melt freeze crust.
点発生乾雪雪崩 Dry Loose snow
Loose dry avalanches can be expected on steep slopes particularly in areas that have received additional overnight snow.
概要
Avalanche
A size 1 skier accidental wet slab avalanche was reported on a SW aspect in the Hanazono backcountry at an elevation of 650m. Multiple natural and ski cut size 1 loose dry avalanches were reported across the region yesterday.
Snowpack
The Northern part of the region received another 10-15cms of overnight snow bringing the settled storm total to ~50cms over the past 4 days. A graupel layer has been found on some polar aspects in Kiroro area which is producing moderate to hard hand shear results down 40cms. The Southern half of the region has received less snow with ~15cms of storm snow overlying the old surfaces. Within the storm snow in this part of the region, there is a density inversion down 10cms that is failing easily above the melt freeze crusts. The old surfaces across the forecast area include a melt freeze crust up to 900m on polar aspects and 1200m on solar aspects as well as wind scoured surfaces on west and North aspects at Treeline and above.
Weather
A Northerly flow continues today as a ridge of high pressure approaches from the West. Steady snowfall is expected to continue through the day with accumulations of up to 10cms in the Southern part of the region (Niseko, Shiribetsu) and up to 20cms in the North (Yoichi area). The new snow will be accompanied by moderate NW winds and mild temperatures rising to near 0C in the valley today. Skies will be overcast all day.
