Avalanche Bulletin
更新日時: 2025/02/10 07:00
Niseko Yotei Yoichi Shiribeshi
Alpine Fair Windslabs have formed in the alpine lee to the NW winds. Cornices have also grown recently and may fail unexpectedly.
Treeline Good Storm instabilities exist at treeline.
Below Treeline Good Storm slabs are the primary concern below treeline particularly on solar aspects and as temperatures rise during the day.
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Monitor instabilities in the storm snow and beware of rising day time temperatures as this will activate the slab properties within the snowpack. The persistent slab continues to be a concern and is best managed with conservative terrain choices. Glide cracks are also opening up and typically form behind convex rolls. Approach convexities with caution.
Avalanche Problem
ウインドスラブ Wind slab
Light to moderate NW and West winds will build windslab on leeward slopes.
ストームスラブ Storm slab
Layers of graupel exist within the storm snow which are producing moderate results on hand shear tests. The storm slab is more of a concern on solar aspects where it overlies a thin melt freeze crust that formed during the sunny period on Feb. 8th.
持続型スラブ Persistent slab
The persistent slab problem exists primarily in the northern part of the region however recent tests have also revealed its presence near Shiribetsu so it may be present in isolated locations across the region. It is now buried quite deep so stubborn to trigger but given the right conditons and terrain, it could wake up and produce a large scale avalanche. Continued caution is recommended with the persistent problem.
概要
Avalanche
Loose dry avalanches were reported on steep slopes in the Eastern part of the region yesterday
Snowpack
30-40cms of storm snow overlies a melt freeze crust on solar aspects. On polar aspects, the storm snow adds to ~100cms of low density snow which overlies the Jan. 28th PWL. No additional tests were conducted on the PWL yesterday and it is becoming increasingly stubborn and isolated however it remains a concern and will continue to be monitored. The mid and lower packs is well consolidated.
Weather
A deep low pressure to the NE of Hokkaido continues to draw a NW flow across the region. As the system moves away, the winds will increasingly trend to the west. Valley temperatures will rise to near zero again today and light snow showers are expected to bring 5-10cms of new snow to most of the region today. Skies will be overcast all day with light to moderate NW winds.
