Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
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Out of date — this forecast expired 3 years ago.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

You can trigger an avalanche large enough to bury you on steep, shady slopes. Wet snow may slide easily due to rain, warm temperatures and sunshine. Move to low angle terrain or make an early exit if you or your machine begin sinking into a mushy surface.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Yesterday (Friday), a party in the Flathead Range experienced whumpfing on East-facing slopes at upper elevations. Audible collapses like these suggest that you can still trigger an avalanche on a layer of weak snow buried 1-2 feet deep. Natural and human-triggered avalanches occurred on mid and upper-elevation slopes facing NW-N-E last Sunday, but we have not received reports of any avalanche activity since then. Warming can consolidate loose surface snow into a slab that is better able to propagate a fracture. 

    Warning signs such as collapsing or whumphing are becoming less common. The chance of remotely triggering one of these slides is decreasing. You may not receive a warning sign until the slope you are on avalanches. This problem is near the surface and can be found by digging beneath last weekend's snow and testing this layer. Default to lower-angle terrain for a safer experience.

     

     

    (4/2/2023)

    This avalanche wrapped from an east-facing aspect to a west-facing aspect. This put debris piles down into two separate drainages. 

    Photo: Tom Whipple

  • Loose Wet

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

    We are on a two-night run of poor refreezes. Current middle elevation temperatures are near freezing, with upper elevations slightly cooler. Any crusts that formed overnight will be thin and break down quickly today. Areas that received rain this morning will be particularly sloppy. Elsewhere, new snowfall will transition to moist with increasing temperatures and potential sunshine. 

    Observations from yesterday (Friday) featured rollerballs and pinwheels on all aspects and elevations but not much in the way of Wet Loose avalanches. The snow surface on northerly slopes has recently transitioned to moist and may be more active today. Choose lower-angle slopes where you or your machine sink more than a few inches into the surface and limit time spent in long-running gullies or above terrain traps where the snow can pile up deep.

    (4/7/2023)

    Biggest pinwheel of the day. Northerly aspects had seen some natural rollerball activity on steep slopes.

Avalanche Discussion

It’s been a while since I’ve woken up to rain. It seems like spring is finally winning out during our last weekend of advisories. Yesterday (Friday), I targeted northerly slopes in the Swan Range to see if any dry snow surfaces were holding out. Alas, I found roller balls, pinwheels, and some impressive glopping instead. Following a second consecutive night with poor refreeze, I anticipate this transition to continue today.

Some areas were lucky enough to pick up several inches of snow overnight. Stahl Peak in the northern Whitefish Range received a surprise 3” of snow and 0.5” SWE. Favored locations have the potential to see a couple more inches of accumulation this morning. New snow combined with moderate southwest winds will start drifting snow into small slabs along ridgelines, saddles, mid-slope gullies and ribs. These should generally be small in size and harmless to a rider unless they knock you off your feet and over a cliff. Consider steering around scalloped surfaces or dune-shaped features if you find more than a few inches of recent snow. New snow that transitions to wet for the first time can destabilize rapidly with warm temperatures and spring sunshine and run further on underlying crusts. 

Sustained warm temperatures increase the likelihood of cornice fall and glide crack failure. Continue to give these hazards a wide berth and stay out from under slopes where they’re looming. 

Have feedback for us? Let us know how we can serve you better. Special thanks to Friends of FAC for creating this survey: link here.

FAC will issue daily forecasts through Easter Sunday, April 9. Following this, we will give snowpack updates several times a week through April as conditions dictate. 

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