Avalanche Bulletin
更新日時: 2022/02/22 07:00
Niseko Yotei Yoichi Shiribeshi
Alpine Fair アルパインエリアでは、ストームスラブの誘発の可能性がとても高い状態です。Storm slab avalanches are very likely to be triggered in the Alpine at present.
Treeline Fair このレベルの危険度の際、ストームスラブの雪崩は、自然発生と人的な誘発、いずれでもとても可能性が高い状態にあります。This latest storm event is very likely to produce natural and human-triggered storm slabs.
Below Treeline Fair 雪崩を発生させうるほどの傾斜があれば、小さい地形であっても、狭い沢や川底などの地形の罠が組み合わさることで、重大な結末となりえます。グライドクラックを斜面上方から視認することは困難です。Micro features that are steep enough to slide may have high consequences especially when combined with terrain traps such as river beds and gullies. Open glide cracks will also be very difficult to see from above.
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Due to northwestern storms and heavy snowfall, field observations during periods of stormy weather were limited. We recommend that you stay away from the avalanche terrain until the latest fresh snow settles down and you can gather more information. With Gale North West winds and a huge amount of new snow we had limited ability for observations during the storm, we recommend staying out of avalanche terrain until the The latest new snow has time to settle and we are able to gather further information.
Avalanche Problem
ストームスラブ Storm slab
長時間の大量降雪と北西の強風により、森林限界とアルパインの標高帯において、ストームスラブが形成しています。過去36時間において、自然発生の雪崩が起こる雪崩サイクルにあったと考えることができ、今後、数日間は、複数の方位にて、人的な誘発による雪崩の可能性が高いままとなります。雪崩地形内の行動は、現時点ではおすすめできません。After a prolonged period of heavy snowfall and gale North Westerly winds storm slabs will have formed in the Treeline and Alpine. We expect a natural cycle of avalanche activity to have occurred over the previous 36 hours and it is very likely human-triggered avalanches can be expected on multiple aspects in the coming days. Backcountry travel in avalanche terrain is not advised at present.
概要
Avalanche
On February 20, an avalanche, size 2, was reported that had enough snow to fill people. The avalanche caused by this storm slab was due to human triggering at an altitude of 1,000 m in Iwaonupuri and on the northeastern slope. There are no injuries caused by this avalanche. A size 2 (large enough to bury a person) was reported on the 20th Feb. This slab was human triggered on a NE aspect on Mt Iwaonupuri at approximately 1000m. There were no reports of injury associated with this incident.
Snowpack
Due to the recent snowstorm, there was a snowfall of well over 100 cm. Before this mass snowfall, melting and freezing crusts were formed on slopes exposed to solar radiation, and slabs were formed locally in the terrain by moving snow to the leeward side in the south wind last week. This snowfall has placed a large load on the old snow and its boundary surface, which has these multiple characteristics. We have now received well in excess of 100cm of new snow during this latest storm cycle. Previous to this loading solar aspects across the South had a crust on the surface. A period of Southerly winds last week redistributed snow onto lee slopes and pockets of slab had formed at higher elevations. This latest snowfall may overload the old snow interface on multiple aspects.
Weather
It is forecast that the effects of the developed low pressure that stagnates in the east of Hokkaido will gradually weaken and begin to show both northwesterly winds and calm. It is said that there will be snowfall until the middle of this week. A deep low pressure system siting East of Hokkaido wil begin to abate on Tuesday with wind speeds dropping to moderate from the North West. We will continue to see snow showers through the mid week.
