Avalanche forecast

Rattlesnake

West Central Montana Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

The snowpack in the Rattlesnake and Seeley zones is generally stable, although snow quality is poor except on the most sheltered slopes. Remember that low hazard doesn’t mean no hazard. Stay alert for red flags and continue to practice safe travel. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    Skiers and riders triggered small, thin windslab on Sunday. These weren’t big enough to bury a person but could push skiers over and into hazards if triggered in the wrong spot.

    Mild temperatures and light winds yesterday gave it a chance to bond, triggering it is now unlikely.

    Steering around steep wind loaded pockets just below ridge line and along the edges of gullies will further decrease your chance of triggering windslab. 

    Shooting cracks in wind drifted snow are a sign of instability and a cue to dial back slope angles. 

     

Avalanche Discussion

Compared to last week, this week's weather is rather benign. Minimal snow fell in the last 48hrs, with most SNOTELS recording an inch or two of fresh. The exception is the central to northern Bitterroot, where about 8” of fresh was noted at upper elevations yesterday. Lolo and Savage Pass SNOTELS indicate around 6” of new snow. Winds have been light out of the southwest for the past 24hr. Another 1-2” will add a bit of snow for transport by today's moderate southwest winds. Mild weather for the next few days will contribute to stable conditions until the next round of snow arrives. 

Last week's winds did a number on snow conditions throughout the forecast area. Conditions are highly variable; anywhere exposed was affected. The fresh snow improved conditions in the Bitterroot but not the Rattlesnake or Seeley. Stiff windboard and exposed crusts are unforgiving and could result in injury or long slides. The best riding is found on protected slopes and in the trees. 

During the presidents day storm, periods of freezing drizzle created crust layers in the snowpack. The depth of these layers varies dramatically because of the strong east winds that followed last week's snowfall. In places, such as east aspects, the crust is on the surface; in others, it is buried up to 18” deep. A layer of facets surrounds the crust in some spots. Elsewhere, it is well-bonded. There have been no recent slides on this layer, and test results have been inconsistent. However, enough have propagated to warrant caution. If you find the crust and soft snow under harder, consider stepping back to mellower terrain. 

Many thanks to the folks who’ve submitted observations; keep sharing what you find out there. 

Ski and ride safe.

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