Avalanche forecast

Swan Range

Flathead Avalanche Center
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Avalanche danger

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

Dangerous avalanche conditions continue in the Swan Range. Thick soft slabs may be reactive to the weight of a rider. Southwest winds will increase throughout the day, drifting snow into thicker and more dangerous slabs along ridge crests. The safest options for enjoying the new snow will be on lower-angled slopes sheltered from the wind. If the warm April sun breaks through the clouds, natural and human-triggered wet loose avalanches will be possible. Move to lower-angled slopes if you feel the snow becoming wet and mushy. 

Avalanche problems

  • Storm Slabs

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

    Today's warming may consolidate recent snow into slabs. The Saturday night and Sunday morning storm left a healthy dose of snow in the Swan Range and Whitefish Range. Slabs will become more widespread as you gain elevation, with the thickest slabs downwind of ridgelines and saddles where southwest winds transported the new snow. Increasing winds today will continue to add mass to these features.

    Look and feel for dense snow that may support the weight of your boards or machine. Monitor new snowfall totals and changes in the snow’s density, and look for shooting cracks, which identify a sensitive slab. Any triggered slides may run long distances and entrain a dangerous amount of snow. Be cognizant of your exposure to features that increase the consequences of avalanches. These include road cuts, gully features, cliff bands, and mid-slope depressions.

    (2/24/2023)

    This image is an example of a soft slab avalanche in a sheltered location on a convexity. This type of avalanche is also known as a storm slab, and we expect them to be found in locations that received the most recent snow.

    Photo: Mark Dundas

  • Loose Wet

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

    Partial clearing skies may allow periods of sustained sunshine to melt the surface snow. Recent snow remained dry above 5500 - 6000 feet, which will be the most likely to be affected. Locations that received the most new snow will be the most susceptible to larger, more dangerous slides. 

    Be on the lookout for snow falling from tree branches or shedding off rock outcroppings as an indicator of the day’s warming. Triggered and natural rollerballs growing in size and distribution prove the surface snow is losing strength. These are all signs to seek out lower-angle terrain free of overhead hazards. Limit your time spent above terrain traps, where debris can pile up and push you into places you don't want to go.

    (4/5/2024)

    Today every aspect had fields of rollerballs. We suspect that increased wet loose activity occurred in the afternoon. We didn't stay around to watch it happen. 

    Photo: Sarah Williams

Avalanche Discussion

Heavy precipitation shut off yesterday morning, bringing impressive water totals in the Swan Range, where Noisy Basin recorded 2.7 inches in less than 24 hours. Stryker Ridge in the Whitefish Range did well, with 1.5 inches in the same time frame. Unfortunately, the Flathead Range and southern and central Glacier Park missed most of the action.

During the storm, wind speeds at favored locations were strong enough to drift the new snow onto leeward slopes. Speeds dropped during the day yesterday but are expected to increase this afternoon and overnight.

Relatively cool temperatures kept the snow dry above 6000', but today's warming and potential periods of sun may melt the surface snow and develop a wet loose problem.

Today is the last daily forecast for the 2023-24 season. We will issue snowpack updates by 5:00 p.m. every Tuesday and Friday through May 3. Thank you for your support this season. 

As you plan your spring backcountry adventures, consider utilizing some weather products on this webpage. You can view a map of all weather stations in our area here. Click on a station for current and recent data viewed in a graph or numerical data. Or view a list of all the stations in this table, giving you similar information in graph and numerical data. Another option is to utilize Snowpack Tracker, a handy graph set that compares the most important mid and upper-elevation stations in our three zones. We encourage using the Missoula National Weather Service home page for great information. You can continue to utilize their Backcountry and Avalanche page through Sunday the 14th. If you haven't visited this page before, it is worth the time, as there are point forecasts for several locations throughout the region and a lot of other valuable data.  If you are heading out of town for a spring riding or skiing adventure, you can access all of the U.S. avalanche centers here.

We encourage everyone to continue submitting observations to our website for the benefit of the spring users. 

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