Avalanche Bulletin
更新日時: 2025/01/19 07:00
Niseko Yotei Yoichi Shiribeshi
Alpine Low With rising freezing levels forecasted today, uncertainty exists
Treeline Fair The new storm snow has had time to settle some. Rising freezing levels can reactivate avalanche activity.
Below Treeline Good Avalanche hazard increases with a rapid increase in temperatures, rain or heavy wet snow.
信頼度：○ good □ Fair △ Low
Travel and Terrain Advice
The rapid rise in temperatures is a strong reason to adopt a cautious mindset today. Challenging riding conditions are particularly evident on south-facing slopes affected by the sun yesterday. As the freezing levels rise today, previously shaded areas below 500 meters will warm up. Glide avalanche activity often increases following warming events like those we experienced today and yesterday. Glide cracks are starting to open up. Finish your riding early to avoid the rapid rise expected. While new snow in the late afternoon could improve riding conditions, it also raises the likelihood of new avalanche activity. Roof avalanches do injure and kill people during rapid warm-ups as forecasted today.
Avalanche Problem
ストームスラブ Storm slab
If warm air and new wet snowfall late this afternoon storm slab activity may increase
点発生湿雪雪崩 Wet Loose snow
As temperatures rise above freezing later today, and possible new wet snow falls loose, wet avalanches on steep slopes may become more possible.
全層雪崩 Glide slab
Roof avalanches and glide avalanches may become a problem today.
概要
Avalanche
No new avalanches were reported yesterday
Snowpack
The new storm snow has had time to settle some yesterday and overnight. Treeline and below, steep solar aspects have gone through a melt-freeze cycle, creating thin crusts. With cooler air temperatures, solar heating ending at sunset, and clear skies overnight allowed for additional radiation cooling of the surface snow. This created High-temperature gradients in the surface snow overnight, particularly on solar aspects. Near crust facets are expected. In some locations open to the sky. Surface hoar may have also formed. NW ridge tops tree line and above have shallower snow packs with some crusty wind-scoured surfaces with deeper snow packs well over 3m on Lee and SW aspects. The mid snowpack has some buried weaker layers consisting of precipitation particles, decomposing fragments, thin crusts, healing surface hoar, and Surface facet tests have resulted in little to no propagation on these weaker layers. The lower snowpack is well bonded yet gliding on the ground, opening glide cracks and increasing the likelihood of glide avalanches on unsupported and steep paths.
Weather
South west flow today with light and tonight bring war air with a rising in the freezing level to 400m later today and tonight. Heavy low elevation snow late in the day is predicted by some of the weather models.
