Avalanche Bulletin
更新日時: 2025/02/06 07:00
Niseko Yotei Yoichi Shiribeshi
Alpine Fair Continued wind loading expected through the day
Treeline Fair Continued wind loading expected through the day
Below Treeline Fair Continued wind loading expected through the day
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Strong winds and blowing snow will make travel at higher elevations difficult today. Staying low in the trees looking for low angle terrain is recommended while the new snow settles and bonds. Make sure to consider overhead hazard from avalanche paths above you. Upper snowpack structure varies greatly across the region, requiring ongoing assessment as you go to different zones. The Jan 28th PWL is still a concern and should be assessed in addition to the new Windslab problem.
Avalanche Problem
ウインドスラブ Wind slab
Ongoing strong winds are creating new Windslabs and Cornices on leeward aspects. Slabs are most reactive when they have just formed.
点発生乾雪雪崩 Dry Loose snow
Use caution in steep features with terrain traps: creeks, gullies, etc.
持続型スラブ Persistent slab
A layer of Surface Hoar, Facets and a Crust that was buried on January 28th is still a concern in the Northern part of the region (Kiroro, Kokusai). An extended column test produced a concerning result on this layer yesterday on a SE asp BTL where Facets overlie a crust, indicating the potential for a slab avalanche to still occur on this PWL. The layer has been found down ~50-90cm in this region.
概要
Avalanche
Several size 1 Windslabs were triggered by skiers in the Kokusai backcountry yesterday on North aspects at TL. A Natural size 1.5 Windslab was observed on Mt Yotei on a NE asp at 1000m yesterday.
Snowpack
35cm new snow overnight at Rusustsu, 20cm at Kiroro. This was accompanied by Strong West and North-West winds, creating new Windslabs and Cornice growth at all elevations. Most areas have been wind affected over the past 48 hours, with sheltered BTL holding the best quality snow. An extended column snowpack test on a SE asp BTL in the Kiroro backcountry yesterday gave a concerning result on the Jan 28 PWL layer down 70cm. The test produced a clean failure on a layer of Facets above the Jan 28 crust that crossed the whole column in one tap, indicating the potential for a slab avalanche to occur on this layer. This shows that the Jan 28 PWL needs some more time to bond to the snow above, and should still be considered when choosing terrain to ride.
Weather
Strong Westerly winds will continue today, with another 10cm of snow forecast by the end of today. Sky will be overcast and temperatures in the -10 range at TL.
