THIS AVALANCHE FORECAST EXPIRED ON March 9, 2019 @ 11:35 pm
Avalanche Forecast published on March 9, 2019 @ 6:35 am
Issued by Zach Guy - Flathead Avalanche Center

Whitefish Range
Flathead Range and Glacier National Park

How to read the forecast

Stability is improving under mild weather.  Stay alert for slabs of drifted snow that formed on Thursday.  These are most common below corniced ridgelines and in gullies where the snow surface shows evidence of wind effect.  Wind protected terrain is offering safe, stable riding.    

2. Moderate

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

1. Low

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

1. Low

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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: Wind Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

A few inches of snow on Thursday accompanied by gusty southwest winds formed thin wind slabs on leeward terrain features.  Observers on Thursday and Friday reported easily triggered slabs and shooting cracks in areas where winds had thickened the recent snow.  Although they are becoming less reactive now, wind slabs remain a concern, especially in terrain where a small slide could push you into harsh consequences.  Use caution in steep gullies, below corniced ridgelines, and in rocky alpine terrain where the winds have been swirling.  Take heed of cracking or thick-feeling snow as a warning sign to move towards more wind protected or wind scoured terrain.  

Forecast discussion

There are a lot of slopes offering good, stable riding today, but trouble is still lurking in terrain with thicker drifts.  The most suspect areas are those that saw a combination of more snow and more wind on Thursday - either high alpine terrain near the crests of the Flathead and Whitefish Ranges, or in the Swan Range snow belt.   The Swan Range reported 7" to 12" through the day on Thursday, while the Flathead Range and Whitefish Ranges saw a few inches or less.  Southwest winds increased through the day and overnight on Thursday, and observers reported easily triggered wind slabs breaking in freshly drifted areas (example A, example B).  Milder weather since yesterday morning is allowing these instabilities to gain strength, especially in areas where slabs are thin and quicker to heal.  In terrain that saw minimal or no wind drifting, you'll find generally stable conditions (example A, example B).  Wind slabs will be slowest to gain strength in areas with the thickest drifts. These are commonly below alpine ridgelines, or downwind of passes and saddles where the winds have larger fetches to collect and deposit the snow into larger slabs.  Pay attention to subtle differences in wind drifting and bonding of these recently formed slabs, and you'll have a trouble-free day in the mountains. 

Weather and CURRENT CONDITIONS
weather summary

A quiet day in the weather is on tap for today: light winds and no accumulating snow.  Clouds start to break up overnight and we'll see sunny weather by tomorrow.  

Two-Day Mountain Weather Forecast Produced in partnership with the Missoula NWS
For 5000 ft. to 7000 ft.
Saturday Saturday Night Sunday
Cloud Cover: Mostly cloudy Partly Cloudy Mostly clear
Temperatures: 20 to 25 deg. F. 4 to 9 deg. F. 23 to 29 deg. F.
Wind Direction: Southwest Southwest Southwest
Wind Speed: 5 to 15 5 to 15 5 to 15
Snowfall: 0" in. 0" in. 0" in.
Snow Line: 0' 0' 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.