Avalanche forecast

Avalanche forecast

Payette Avalanche Center
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Avalanche danger

Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Triggering a persistent slab avalanche on old snow from November remains unlikely. You could get into trouble in steep, north-facing terrain, where shallow snow rests on rocks. Unburied obstacles and a melt-freeze crust that blankets much of the snow surface, continue to make off-trail travel difficult.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1–2

    Old weak snow from November continues to show signs of strengthening (albeit slowly). Triggering an avalanche within this old snow today is unlikely. Unlikely does not mean impossible, especially in steep (greater than 35 degrees), north-facing terrain where shallow snow exists over rocks. You will not see any warning signs like cracking or collapsing. Your best way to manage this avalanche problem is to avoid the terrain where it is most likely hiding. 

    We continue to highlight this problem because this old November snow will likely be tested in the upcoming days and week. Consistent snowfall in the forecast will produce a strain on buried weak layers. If we receive a significant amount of snow during a short period, we could see avalanches failing on this old snow.

Avalanche Discussion

A CHANGE IS GONNA COME

I can hear Sam Cooke singing now. "It's been a long/A long time coming, but I know/A change gon' come". Yes folks, a weather pattern change is on the horizon and that does mean snow is consistently in the forecast. Let me say that again in case your caffeine hasn't kicked in. Snow is in the forecast. Yesterday, our forecast area was brushed by a storm to our south. Tonight, some mountain locations may see 1-3 inches. Saturday into Sunday another Pacific storm could bring more snowfall to the region. This pattern looks to continue for most of next week. What does this mean for our lonely snowpack that has been sitting on the ground for months now waiting for its friends to grow? Read on to find out.

Although the facets from November have been slowly gaining strength, snow in the middle and upper snowpack have been losing strength. Yesterday, we found a widespread crust and facet sandwich near the surface on many aspects, along with buried surface hoar hiding at upper elevations. You can read my observation here.  A weather pattern change is upon us and consistent snowfall and colder temperatures are in the forecast. New snow means buried weak layers will undergo a strength test. Two important questions are: How much snow and over how much time? A lot of snow in a short period of time rapidly increases the likelihood of widespread natural and human-triggered avalanches. However, small amounts of snow over a longer period of time add a little bit a stress, a little stress, a little more, until it's too much. As new snow begins to fall this weekend and next week, what are impatient snow lovers to do? Remain vigilant. Pay attention to snowfall and weather changes. Watch for red flags like rapid loading. Look for obvious signs of instability like collapsing (or whumpfing) and shooting cracks. Of course, the best signs of instability are recent avalanche activity.

The best way for us to know what's happening as more people are out in the mountains is to submit an observation. Submitting an observation improves your skills, informs other users, and benefits avalanche forecasts. Simple photos highlighting conditions are very helpful.

Did you know there will be a AIARE Level 1 Avalanche Class specifically for Motorized Users? Check out our classes and events page to learn more.