モイワ山麓＋3度未明降雨 モイワ800m-0.6度南東3.0m湿雪降雪未明までわずか 見返り800m -5度東南東2.0m湿雪降雪 ヒラフ花園1000m-0.6度南東3.0m 花園800m-0.1度南南西6.4m 日本海弁慶岬南8m 神威岬南9m気圧1015hPa波高0.8波高m。
日本海を低気圧が北上し暖気流入、新たな降雪はわずか、ニセコは未明にかけて雨、雪は緩み融雪が進む。
この情報は事故防止のために続けられており、多くの事故が悪天候下で起こっていることから、気象推移によるふきだまりの発達過程の観測とそれを数値で確認する各データの変化を危険判定の目安としている。吹雪によって急激に風下に堆積して量を増すふきだまりは風が弱まるまで構造的に不安定な状態が続く。そこを刺激すれば瞬時に広い面積が破断して面発生表層雪崩を起こす。確かに雪崩は弱層から起こる、しかし雪崩が起こる前にピットチェックでそれを予測するのは不可能ではないが大変困難と言える。事故後に原因がわかっても後の祭りであり死者は還らない。吹雪の中で風下斜面を刺激しないことが事故防止には最も確実な対処法でありニセコではそのためにゲートの開閉を行っている。知識への過信が事故を起こす。大勢が吹雪の危険を正しく理解してそれを常識とすれば事故は起こらない。
天候急変に注意。このスポーツに安全はない。良い一日を。
Moiwa base +3℃, raining at pre-dawn. Mowia 800m: -0.6℃, SE3.0m/s, some wet snowfall at pre-dawn. Mikaeri 800m: -5℃, ESE2.0m/s, wet snowfall. Hirafu Hanazono 1000m: 0.6℃, SE3.0m/s. Hanazono 800m: -0.1℃, SSW6.4m/s. Sea of Japan Benkei cape S8m/s, Kamui cape S9m/s, 1015hPa, 0.8m waves.
A low-pressure system is moving north over the Sea of Japan, bringing an inflow of warm air. New snowfall has been minimal, and Niseko experienced rain through the early morning, causing the snowpack to loosen and melt.
This information is provided continuously to prevent accidents. Given that many incidents occur during severe weather, we base our danger assessments on the observation of wind slab formation and the numerical analysis of shifting weather data.
Wind slabs that accumulate rapidly on leeward slopes during blizzards remain structurally unstable until the winds subside. Any stimulations in these areas can cause a wide-range fracture, leading to an instantaneous soft-slab surface avalanche. It is true that avalanches originate from weak layers; however, predicting them through pit checks before they occur—while not impossible—is extremely difficult. Understanding the cause after an accident is too late, and will not bring back those who have been lost.
Avoiding stimulating the leeward slopes during a blizzard is the most reliable way to prevent accidents. This is precisely why Niseko manages the opening and closing of the gates. Overconfidence in one’s own knowledge often leads to disaster. If everyone correctly understands the dangers of a blizzard and treats that knowledge as common sense, accidents can be avoided.
Please stay alert for sudden weather changes. Remember, there is no such thing as absolute safety in this sport. Have a great day.
出典 Source：気象庁 JMA website (www.jma.go.jp/bosai/weather_map/)