Avalanche Advisory published on February 22, 2019 @ 6:27 am
This Avalanche Advisory expires in 12 hours, 38 minutes
This advisory is valid for 24 hours
Issued by Melissa Hendrickson - Idaho Panhandle Avalanche Center

St. Regis Basin/Silver Valley

bottom line

The snow from last week has continued to strengthen over the past several days without any new loading on top of it.  We still have reactive wind slabs on multiple aspects as we've had varied wind directions this week.   And our buried persistent weak layers are still down there lurking in the pack.  Assess your riding area before committing to steep, complicated terrain.

How to read the advisory

St. Regis Basin/Silver Valley

How to read the advisory

The snow from last week has continued to strengthen over the past several days without any new loading on top of it.  We still have reactive wind slabs on multiple aspects as we've had varied wind directions this week.   And our buried persistent weak layers are still down there lurking in the pack.  Assess your riding area before committing to steep, complicated terrain.

2. Moderate

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

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

1. Low

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Below Treeline
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.
Avalanche Problem 1: Wind Slab
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Wind slabs are our main concern out in the backcountry right now.  We've had winds from our normal S-SW direction, but they have been switching to the N as well.  As a result we have wind slabs that can be found on all aspects above treeline. Heads up for cross loaded gullies and wide open slopes as well.  Expect more wind slab development over the next couple of days in our traditional N-NE loading zones as the winds come from the S-SW during the storm on Friday through Friday night.  

 

Avalanche Problem 2: Persistent Slab
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We are keeping our eyes on an ice crust with associated rounding facets that we are finding about a half a meter down in the pack. Temperature gradients show this to be gaining strength, but it was still popping in pit tests (see photo).  This can be found on all aspects.  Buried surface hoar can still be found in isolated locations on the NW-N-NE aspects.   We will continue to keep an eye on these layers.  

recent observations

We toured at the Goose Peak area yesterday and found overall good stability and lots of Vitamin D.  One other thing to note is that we found surface hoar development from the cold, clear weather we had yesterday and the night before.  Hopefully this doesn't get buried intact, but if it does, expect the avalanche danger to rise on Friday night with the new loading.  

Weather and CURRENT CONDITIONS
Two-Day Mountain Weather Forecast Produced in partnership with the Spokane NWS
For 2000 ft. to 4000 ft.
Today Tonight Saturday
Weather: Slight chance snow then snow snow then Snow likely chance snow
Temperatures: 26 deg. F. 22 deg. F. 29 deg. F.
Wind Direction: S S SW
Wind Speed: 5-8 8 7
Expected snowfall: 1-2 in. 2-4 in. <1 in.
For 4000 ft. to 6000 ft.
Today Tonight Saturday
Weather: Partly Sunny then Mostly Cloudy and Breezy Snow and Breezy Snow
Temperatures: 19 deg. F. 16 deg. F. 21 deg. F.
Wind Direction: SW SW W
Wind Speed: 10-15, G29 18-24, G33 10-14
Expected snowfall: 1-2 in. 3-5 in. 1-3 in.
Disclaimer

Avalanche conditions change for better or worse continually. Backcountry travelers should be prepared to assess current conditions for themselves, plan their routes of travel accordingly, and never travel alone. Backcountry travelers can reduce their exposure to avalanche hazards by utilizing timbered trails and ridge routes and by avoiding open and exposed terrain with slope angles of 30 degrees or more. Backcountry travelers should carry the necessary avalanche rescue equipment such as a shovel, avalanche probe or probe ski poles, a rescue beacon and a well-equipped first aid kit.  For a recorded version of the Avalanche Advisory call (208)765-7323.

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