Avalanche forecast

Rattlesnake

West Central Montana Avalanche Center
View on map

Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
Open full map
Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Persistent slab avalanches remain a low-likelihood, high-consequence concern on upper elevation north aspects. Pockets of reactive windslab may be found just below ridgelines and along the edges of gullies.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3

    Skiers and riders could trigger persistent slab avalanches up to 5 feet deep on northerly aspects at upper elevations. Triggering one is unlikely but not impossible. This is a low-likelihood, high-consequence scenario. 

    The Rattlesnake has both buried depth hoar and basal facets above 7000' that show some reactivity.

    Choosing slopes under 35º and avoiding trigger points like convex rolls and thin spots around rocks and windswept ridges is the best way to manage this problem. 

    Dig before stepping into steeper terrain. If you find soft sugary snow under a stiffer slab, step back to mellower slopes. These layers will likely not give a warning before failing, and their presence can only be ascertained by looking in the snowpack.

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Winds have been light and predominantly westerly for the past 48 hours, there has been little snow transport, and warm temperatures are helping wind slab bond. However, pockets of reactive windslab may remain just below ridgeline and along the edges of gullies. While mostly small, these are large enough to carry skiers and riders into hazards such as terrain traps. Check for red flags, such as shooting cracks on representative slopes before committing to terrain over 35º, and avoid skiing on wind loaded pockets.

Avalanche Discussion

It’s been a mild week for weather, just a trace of new snow, light winds, and mild temperatures. As a result, there isn’t much new to report on avalanche stability.

The hazard is improving and trending lower. However, facets on upper elevation north slopes keep it at moderate. There is still too much uncertainty about the layer to remove it from the problems. Poor structure can still be found, weak sugary snow sits under a cohesive slab, and stability tests point to the possibility of triggering a slide. This is a low likelihood/high consequence problem. There is lots of good riding at other aspects and elevations, and given the destructive potential of this problem, it’s best to give it more time to bond.

Where there is a supportive crust from the Christmas rain, there is little likelihood of triggering a slide. However, where the crust is thin, a possibility of triggering a slide on weak layers remains. Remember, low danger doesn’t mean no danger. 

Continue to practice safe travel. Assess the snowpack, stay alert for Red Flags, ski and ride one at a time, and stop in safe zones. If in doubt about the stability, step back to slopes less than 35º.

Please submit an observation, even if it's to tell us that the stability and skiing were good. That’s valuable information.

Ski and ride safe.

Regions covered