Note: this bulletin is published in the pm and effective for the following day. Be alert to differences in the forecast and actual snowfall amounts and weather activity overnight.
Backcountry Avalanche Danger Rating
Upper (>1000m): CONSIDERABLE
Mid (800-1000m): CONSIDERABLE
Lower (<800m): MODERATE
Current Avalanche Problems
Wind Slab | Likelihood: Possible | Size: small-medium
Loose Dry | Likelihood: Very Likely | Size: small
Looking at tomorrow’s backcountry hazard level, I find myself coming back to the old rules of thumb. The danger is going to be elevated anytime we see a notable change in weather and/or new stress on the snowpack. It’s all too easy to get caught up in the game of putting all the puzzle pieces together and losing sight of the big picture. We had a spell of warmer days (12/22-23) which had varying effects on the surface conditions, none of which are likely to improve snowpack stability once those surface layers are buried. Those surface layers are now buried. We’ve had a few days of modest snowfall and if the forecast models validate, tonight and tomorrow will see the biggest new load of the week. Winds were calmer today, but have been blowing steadily over the last couple of days. I have not been in the backcountry since the 23rd, so little to go off of in terms of observations, but my guess is that much of this Christmas storm cycle’s new snow is landing on firm surfaces (due to wind slabs up high, and due to melt/freeze crusts down low). I haven’t seen any indication of reactivity in the current storm layer… it’s skiing quite nice!
That said, we’ve seen a few notable weather events this week (warming temps, melt-freeze cycles, and high winds). We are now seeing a new stress with this storm’s accumulation. I’m bumping my hazard assessment for tomorrow up to CONSIDERABLE at upper and middle elevations, and MODERATE down low. The most likely problem will be Dry Loose avalanches (ie, ‘sluff’). While these are expected to be very likely and widespread, they also tend to be small and relatively inconsequential. While skiing sustained steep features, be alert to loose snow moving around you as you go so you don’t get knocked off your feet in a bad spot. The less likely, but more consequential problem, would be triggering a buried windslab avalanche. These could be much larger and may propagate across larger terrain features (ie, an entire bowl or slope). Be on the lookout for signs of wind loaded snow (cornice development, changes in surface penetration/surface hardness) and act accordingly.
As a local guide and avalanche professional, I have chosen to share this hazard assessment in the interest of encouraging better information sharing within the local community. This avalanche bulletin is to be used at your own risk and is based on very limited data gathered by myself and other guides working for Japan Powder Connection. Please use this information in addition to other resources and take responsibility for your own actions in the backcountry. Also, please respect and abide by all Niseko Area Rules. This information applies only to backcountry areas accessed externally from area resorts. This information is published the evening before and in effect for the following day.
As always, remember that making good decisions in the backcountry takes years of practice and experience. Having the gear is a small part of the equation. Take an avalanche safety course and hire a properly trained guide so you don’t learn the hard way!
Japan Powder Connection - Professional Backcountry Guides and Instructors
Niseko Avalanche Information - Niseko’s avalanche information page. Not a ‘bulletin’ by Western standards, but Shinyasan has been doing this for 20+ years and knows these mountains far better than myself.
Snow-Forecast - Niseko Area Weather Forecast
Niseko Now - Local Weather and Conditions Summary