THIS AVALANCHE ADVISORY EXPIRED ON February 14, 2018 @ 6:51 am
Avalanche Advisory published on February 13, 2018 @ 6:51 am
Issued by Jeff Thompson - Idaho Panhandle Avalanche Center

Selkirks/Cabinets

bottom line

Cold temperatures and strong winds have driven some change in the snowpack. The cold temperatures over the past 72 hours have frozen the top of the snowpack. It's pretty locked up and won't change to much until we see warmer temperatures or more snow. Meanwhile...the strong winds have transported a fresh wind slab on to windward slopes.  These newly formed wind slabs are sitting on older wind slabs that are capable of breaking off in the form of an avalanche

How to read the advisory

Selkirks/Cabinets

How to read the advisory

Cold temperatures and strong winds have driven some change in the snowpack. The cold temperatures over the past 72 hours have frozen the top of the snowpack. It's pretty locked up and won't change to much until we see warmer temperatures or more snow. Meanwhile...the strong winds have transported a fresh wind slab on to windward slopes.  These newly formed wind slabs are sitting on older wind slabs that are capable of breaking off in the form of an avalanche

2. Moderate

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

1. Low

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Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

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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  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

the Selkirk and Cabinet mountains have seen a lot of wind in the past 30 hours. Look for fresh wind etching while your traveling in the backcountry.  Fresh wind etching is a clear sign that snow was moving from one location to another. Most of the time that translates into fresh wind slabs on windward slopes. Use extra caution when navigating along ridge lines or near cornices.

Avalanche Problem 2: Persistent Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

I still need to mention buried persistent layers. There are multiple weakness buried in the snowpack still. None of the buried weaknesses are very reactive when we conduct tests, but they are still there and capable of producing avalanches. Shallow spots in the snowpack (trigger points) are places you could initiate an avalanche on one of those layers.  Small terrain features right around treeline are the most concerning. Make good travel choices and avoid terrain traps.

Weather and CURRENT CONDITIONS
Weather observations from the Region
0600 temperature: 21 deg. F.
Max. temperature in the last 24 hours: 28 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 19 mph
Maximum wind gust in the last 24 hours: 48 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 280cm inches
Two-Day Mountain Weather Forecast Produced in partnership with the Spokane NWS
For 2000 ft. to 4000 ft.
Tuesday Tuesday Night Wednesday
Weather: Increasing clouds Snow Snow
Temperatures: 33 deg. F. 30 deg. F. 32 deg. F.
Wind Direction: S S SW
Wind Speed: 6-8 3-5 3-5
Expected snowfall: 0 in. 3-7'' in. 2-4'' in.
For 4000 ft. to 6000 ft.
Tuesday Tuesday Night Wednesday
Weather: Increasing clouds Snow Snow
Temperatures: 27 deg. F. 24 deg. F. 24 deg. F.
Wind Direction: SW SW SW
Wind Speed: 12-14 14-16 7-10
Expected snowfall: 0 in. 4-8'' in. 2-4'' 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.