Avalanche Bulletin
更新日時: 2025/02/21 07:00
Niseko Yotei Yoichi Shiribeshi
Alpine Fair Uncertainty exists regarding bonds within the storm snow and the distribution of the windslab.
Treeline Fair Uncertainty exists regarding bonds within the storm snow and the distribution of the windslab.
Below Treeline Fair Uncertainty exists regarding bonds within the storm snow and the distribution of the windslab.
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
Yesterday`s avalanche activity indicates that the storm and windslab have been reactive and will need more time to settle and bond to the previous surfaces. A cautious approach is recommended today as you evaluate layers within the storm snow. The storm and windslab problems are best managed by avoiding large, open slopes and convex rolls. Be particularly careful if there is strong solar input and a rapid rise in temperature where you are travelling today.
Avalanche Problem
ウインドスラブ Wind slab
Previous NW winds have caused windslab and cornice growth on leeward slopes.
ストームスラブ Storm slab
Cooler temps, more cloud cover and the benefit of time will improve the bond of the storm snow to the previous surfaces. Use extra caution if there is strong solar input or a rapid rise in temperature today as this will cause the storm slab to become more reactive.
点発生乾雪雪崩 Dry Loose snow
The loose dry problem is isolated to the Kiroro/Kokusai region that received 20cms of overnight snow and is expecting more snow through the day today.
概要
Avalanche
A size 2 Skier accidental storm slab avalanche occurred on a NE slope in a backcountry area to the west of Kiroro resort at 900m. Skier was taken for a ride and impacted a tree resulting in a broken leg and evacuation by helicopter. Another size 2 skier accidental storm slab avalanche was reported in a backountry area on an open BTL slope to the North of Kiroro resort on a NE aspect at 800m resulting in a short ride and no injuries for 1 skier. Several other smaller loose dry, wind and storm slab avalanches were reported in Niseko backcountry areas yesterday.
Snowpack
Solar input yesterday caused rapid settlement of the recent storm snow. In the north of the region (Yoichi area) storm snow has settled to ~80cms and remains reactive on the old/new bond. In the south of the region (Niseko, Yotei, Shiribetsu) storm snow depth is ~40cms. Most solar aspects across the region developed a melt freeze crust up to 1000m as a result of yesterday`s sunny weather. A graupel layer was observed on the snow surface in the North of region and may become a problem when we receive our next snowfall. The Jan. 28th PWL remained unreactive during the most recent storm cycle despite heavy loading.
Weather
A ridge of high pressure has established itself over SW Hokkaido. Winds are expected to be light from the NNW with the occasional light snow shower at times through the day. Skies will be broken with sunny breaks. Temperatures are forecasted to reach a high of -1C in the valley today.
