Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A tale of two cities today. At low and mid elevations, prolonged warming and rain make wet snow avalanches the primary hazard. At upper elevations, the main concern is triggering recently-formed slabs of drifted snow. Your altimeter and the surface snow conditions can indicate which hazard is a concern on a given slope. Sticky snow or rollerballs? Wet snow. Hard, hollow-feeling snow? Wind Slabs. Dry, soft snow on a slope less than 35 degrees? Golden ticket.

Avalanche problems

  • Loose Wet

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

    Triggered or natural wet snow avalanches are possibe today on slopes steeper than about 38 degrees where you find about 6 inches of moist or wet snow. That's snow that forms easily into snowballs. These can be dangerous above terrain traps or on continuously steep slopes where moving snow can entrain more debris as it descends. The dense debris in these slides can easily knock a person off their feet or snowmachine and can be very hard to escape. Large wet loose slides will be more widespread in the Flathead Range and Lake McDonald area, where many travel routes cross the runouts or tracks of mid-elevation avalanche paths. Avoid being on or under steep slopes if you see natural or triggered rollerballs, particularly if you are above terrain traps like gullies. 

    (1/12/2022)

    Cam chucked a snowball at a steep slope and triggered rollerballs in the wet surface snow

    Photo: Johnson

  • Wind Slabs

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

    Dense or hard slabs of drifted snow exist at upper elevations on the lee sides of ridges, downwind of saddles and passes, on the sheltered sides of gullies and couloirs, and in other terrain features that collect blowing snow. Many of these will be hard and prone to break unpredictably, making slope cuts a risky means of gathering feedback. Look for softer snow and better riding on upper elevation slopes sheltered from the wind. Falling cornices can spontaneously trigger these slides.

    (1/11/2022)

    A lot of wind transport was observed as well as a lot of shooting cracks on wind-loaded features around my split board.

    Photo: Zach Dugan

Avalanche Discussion

A good time to be an enlightened monk or nun and accept the transition of dry, stable snow to wet snow or crusts as part of an inevitable cycle. But it happened so quick. Sigh. Best of times, worst of times,  I guess.

Rain and above-freezing temperatures have left the surface snow wet or moist at low and mid elevations Near-surface rain crusts are breaking down at these elevations. The transition back to dry snow is probably between 6000 and 6500 feet. Most stations below 5000 feet have not recorded freezing temperatures since Tuesday afternoon, except for a few pockets of inversions. Mid-elevation stations are showing above freezing air temperatures after early Wednesday morning, with rain or heavy, wet snow until late Wednesday afternoon. The above-freezing temperatures look to continue until tonight, with some brief sunny moments that may accelerate the warming. A weak trough may bring a few more inches of wet snow to the region. 

At upper elevations, it still feels like winter. Recent deposits of wind-drifted snow are the primary avalanche hazard. Since Tuesday, weather stations above 6500 feet have shown moderate to strong southwesterly winds with some extreme gusts. Dense, hard slabs have likely formed in terrain that collects wind-blown snow. You can trigger these most easily from thin spots near their edges or from below. These should stabilize as wind diminish overnight.

Several parties reported that difficult travel conditions forced them to turn back before reaching their objectives Wednesday. Sticky snow meant skis were a means of transporting snow rather than transport across snow. They recommended skin wax. 

Refresh yourself on the distinction between elevation bands here. 

Regions covered