Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Tropical temperatures overnight result in dangerous avalanche conditions. A very large natural avalanche occurred yesterday, with the possibility of similar activity today. You could likely trigger a slide in the mushy surface snow. Choose slopes less than 35 degrees in steepness and free of overhead hazards.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3

    The warm overnight temperatures may not allow more than a superficial refreeze of the snow surface. If there is a crust, it should break down quickly with today's balmy conditions. The near-surface layers are becoming saturated, and natural wet loose slides may develop. The chance of triggering a slide in the mushy surface snow is increasing. Thick mashed potato-like snow and rollerballs are clues that you need to move to a different aspect or elevation band. Choose slopes less than 35 degrees in steepness not connected to overhead avalanche terrain. Limit your time spent on or below sunny slopes this afternoon.

    (3/27/2022)

    Large natural wet loose avalanche near the top of Werner Peak.

    Photo: Scott Rolwey

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3

    Weak layers 1-3 feet below the surface still have the potential to result in a slab avalanche. A rider's weight or snowmachine may affect these layers resulting in a slide. A cornice fall or wet loose slide could be enough mass to trigger an avalanche. Choose planar or concave slopes to maximize your chances of having a safe, uneventful day. Choose slopes less than 35 degrees in steepness and limit time spent traveling beneath steep slopes, especially as the day warms up.

    (3/26/2022)

    The crown line of a large Persistent Slab avalanche on Link Mountain. This avalanche likely occurred March 23, during the second day of warm temperatures with a poor overnight refreeze. The debris crossed the Red Meadow Road.

    Photo: Cam Johnson

  • Cornices

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

    The likelihood that sizeable seasonal cornices will fail is increasing. The seventh day of sustained warming may result in cornice sections beginning to calve off. Van-sized chunks of snow may trundle down the slope and could initiate a large slab avalanche on a buried weak layer. While traveling along ridgelines, give these features a wide berth because they are notorious for breaking further back than anticipated. Limit your time spent on slopes beneath these beasts.

    (3/17/2022)

    Large seasonal cornices are found along many ridgeline locations.

    Photo: Adam Clark

Avalanche Discussion

Monday is the seventh consecutive day of well above average daily high temperatures and warm overnight lows, resulting in a poor or no refreezing of the snow surface. Sunday's high temperatures were the warmest of the week, with mid-elevation stations reaching the low to mid-50s and upper elevation stations reaching mid to upper-40s. Low temperatures this morning are also the highest of the week, with nearly all stations well above freezing and 4-9 degrees warmer than yesterday. 

This morning's tropical temperatures keep the avalanche danger elevated, with the threat of a triggered slide likely. Unlike previous days, today's hazardous conditions will begin early. One example of the ridiculously warm readings is on the ridge of Mt Aeneas at 7186 feet, where it was 40 degrees at 4:00 a.m. Today's mindset should continue with the theme of unusual conditions leading to unusual avalanches. Due to the lack of a refreeze, this is more true today than in the previous six days. I recommend staying off of and out from underneath all avalanche terrain. A cold front arrives early Tuesday, strengthening the snowpack allowing for safer conditions for the remainder of the workweek. 

For a sunny and warm weekend, observations were scarce. We received a report of a very large avalanche that occurred during the day Sunday on Mt Stanton in GNP. The photos submitted to our Facebook page were taken through a telescope but showed a large avalanche that failed or stepped down to the ground. Debris may have traveled 3000 vertical feet. We hope to get a better view of this slide today. A curious observer in the Swan Range noted a breakable 1-2 inch crust with fresh rollerballs. A snowmobiler in the southern Whitefish Range pointed out a wet loose avalanche near the top of Werner Peak.

Do you know that we produce a text and video weekly summary of snowpack, weather, and avalanche conditions? You can find this in the Conditions Blog below the Bottom Line or here. Megan, the FAC March intern, wrote this week's summary before heading back to grad school in Oregon.

Join us for our last education event of the season. Topics Class! The Scoop on Spring Touring, Wednesday, April 6th, 6:30 to 7:30. No registration is necessary for this in-person event.

 

 

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