THIS AVALANCHE FORECAST EXPIRED ON December 26, 2019 @ 12:25 am
Avalanche Forecast published on December 25, 2019 @ 7:25 am
Issued by Zach Guy - Flathead Avalanche Center

Flathead Range and Glacier National Park

How to read the forecast

Numerous destructive avalanches ran last weekend in the Flathead Range and Glacier Park.  Although the snowpack continues to recover from last weekend's storm, triggering a large and dangerous persistent slab remains a possibility.  The lingering concern - slabs several feet thick over early-season weak layers - are most likely to be triggered from steep, high elevation terrain with variable snow coverage or unsupported rollovers.  Use caution in alpine terrain.  

2. Moderate

?

Above 6500 ft.
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

1. Low

?

5000-6500 ft.
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

?

3500-5000 ft.
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
  • 1. Low
  • 2. Moderate
  • 3. Considerable
  • 4. High
  • 5. Extreme
Avalanche Problem 1: Persistent Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

In the Flathead Range and Glacier National Park, we have observed a number of thick, hard slabs that ran naturally last weekend, one of which put 20 feet of debris in the valley below.  Under our current weather pattern, persistent slabs 2 to 4 feet thick are becoming more difficult to trigger.  Near and into upper elevations, the snowpack structure remains worrisome and needs more time to recover from last weekend's impressive loading event.  Be cautious of steep upper elevation terrain.  You are most likely to trigger a thick, hard slab from a thin spot on the slope. Shallow trigger points are more common in complex, alpine terrain with rocks and cliff bands.  

Forecast discussion

Twas the night before Christmas, when all through the peaks

Not a snowflake was falling, the winds had ended their streak;

The beacons, shovels, and probes were packed with care,

In hopes that more powder soon would be there;

The faceted crusts lay quietly lurking below 3 feet of snow

Still demanding caution for those wanting to go;

The danger was most acute in The Flathead and Glacier Park

Where a handful of D3’s last weekend have left their mark;

From Friday's warm, wet, and wind arose such a clatter,

Observers sprang from their ventures to relay what was the matter;

The sun on the breast of the windblown snow,

Gave the lustre of crowns and avalanche debris below;

Off Furlong, off Nyack, off Cameahwait and Snowshed,

These are the slides that keep me restless in bed;

For fear that a skier or rider might trigger the same,

While crossing a shallow spot in upper elevation terrain;

Although stability is now improving, keep caution in site,

Happy Christmas to all, and to all a good night!

Merry Christmas from the Flathead Avalanche Center.  For a more technical, albeit less festive discussion on our current snowpack, take a look at yesterday's forecast discussion, which still applies.    

 

Weather and CURRENT CONDITIONS
weather summary

Up to 3" of new snow fell yesterday at all elevations, treating us to a White-ish Christmas.  Today should be dry with cloud coverage dissipating into tomorrow.  Winds remain light until a weak system approaches on Thursday afternoon which should bring light snowfall on Friday.  Temperatures are in the teens and 20's this morning; they will remain cool throughout the rest of the week.  

Two-Day Mountain Weather Forecast Produced in partnership with the Missoula NWS
For 5000 ft. to 7000 ft.
Wednesday Wednesday Night Thursday
Cloud Cover: Mostly Cloudy Partly Cloudy Partly Cloudy
Temperatures: 20 to 25 deg. F. 9 to 14 deg. F. 18 to 23 deg. F.
Wind Direction: West Northwest Southwest
Wind Speed: 5 to 10 5 to 10 5 to 15 G20
Snowfall: 0" in. 0" in. 0" in.
Snow Line: 1000' 500' 0'
Disclaimer

This forecast applies only to backcountry areas outside established ski area boundaries. The forecast describes general avalanche conditions and local variations always occur. This forecast expires at midnight on the posted day unless otherwise noted. The information in this forecast is provided by the USDA Forest Service who is solely responsible for its content.