Avalanche forecast

Swan Range

Flathead Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Recent snowfall has created dangerous avalanche conditions at upper elevations. A rider can trigger large slabs or sluffs in the new snow. Choose low-angle slopes that are not exposed to overhead hazards, like avalanche paths.

Our last scheduled daily forecast is Tuesday, April 8th.  We will continue to produce snowpack updates twice weekly on Tuesdays and Fridays.

Avalanche problems

  • Storm Slabs

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

    The snowfall has tapered off, but the hazard of triggering a large avalanche remains. Soft slabs may break within the new snow or on the crust below. These will be thickest and most sensitive to a rider where southwest winds are drifting snow. Expect greater hazard as you gain elevation and at the tops of chutes and leeward slopes. 

    Use small and inconsequential slopes to test how the new snow is bonding to the crust below. If your tests produce shooting cracks, small slabs, or sensitive sluffs then you can expect avalanches on larger, steeper slopes with more than 8 inches of new snow. 

    (3/15/2025)

    It is still possible to trigger soft slabs in the fresh snow.  

    Photo: Flathead Avalanche Center

  • Loose Wet

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

    You can trigger sluffs in the new snow.  These will range from wet to dry as you climb in elevation.  Snow shedding from trees or rocks can cause sluffs to run naturally. Sluffs may travel further than you expect on an underlying crust. The most dangerous slopes are very steep, and above terrain traps, including tree wells.

    Thin surface crusts may have formed overnight on any slopes that warmed yesterday. These crusts will make wet loose avalanches unlikely during the morning but could break down with above freezing daytime temperatures.  Steep, rocky slopes are typically the first to slide. Move off of and out from steep slopes if you notice fresh rollerballs or small point releases. 

    (4/1/2025) 

    Recent snow may sluff easily and run long distances on a stout melt freeze crust.  

    Photo: Brian Merewitz

Avalanche Discussion

We kicked off April with some impressive snowfall in parts of the advisory area. In the Northern Whitefish Range, Stahl Peak recorded 1 foot of new snow (1 inch SWE) in the last 36 hours. During that same time Noisy Basin, in the Swan Range, picked up 4 inches of SWE and over 20 inches of snowfall. Elsewhere, observations reported 8 inches of new snow (WMR, Marion). Comparatively, today's snowfall should be pretty minimal. Tomorrow will be another storm day. 

Natural avalanche activity likely peaked Tuesday morning during the most intense snowfall. The avalanche danger is decreasing today but there are several factors contributing to uncertainty:

  • Lack of observations from the upper elevation band
  • Convective afternoon snow showers could cause variable accumulations
  • Bonding (or lack thereof) of the new snow to the underlying crust

Below the new snow, my confidence increases. Rain and warming during late March likely "crushed and flushed" any lingering weak layers.  If not, a thick and supportable melt-freeze crust has formed on all aspects well into upper elevations, making it unlikely you will trigger any deeper instabilities.

Wanna help your crew stay safe? Eastern Oregon University is conducting a survey to better understand avalanche safety preparedness among motorized backcountry users. The survey will help us learn more about who is purchasing and practicing with avalanche rescue gear (beacon, probe, shovel) and participating in avalanche education—and why some riders are not. The survey is confidential and anonymous. Your feedback is invaluable in improving avalanche education and awareness. Please take a moment to share your experience and help us make a difference:

https://eoustmhs.qualtrics.com/jfe/form/SV_3L8QKAuZzcxJBLo

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