THIS AVALANCHE ADVISORY EXPIRED ON January 31, 2018 @ 6:30 am
Avalanche Advisory published on January 30, 2018 @ 6:30 am
Issued by Jeff Thompson - Idaho Panhandle Avalanche Center

Selkirks/Cabinets

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A new advisory and a new avalanche problem to talk about! Even though buried persistent layers and deep slab instabilities are still a concern, the bigger issue is the precipitation falling on the snowpack right now. Upper elevations are seeing light snow and strong winds while the lower elevations are seeing rain.  Be aware of wind transported snow up high and rain on snow down low.  Based on temperatures, it looks like the rain snow line is at 4,500-5,500 ft.

How to read the advisory

Selkirks/Cabinets

How to read the advisory

A new advisory and a new avalanche problem to talk about! Even though buried persistent layers and deep slab instabilities are still a concern, the bigger issue is the precipitation falling on the snowpack right now. Upper elevations are seeing light snow and strong winds while the lower elevations are seeing rain.  Be aware of wind transported snow up high and rain on snow down low.  Based on temperatures, it looks like the rain snow line is at 4,500-5,500 ft.

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

2. Moderate

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

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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Watch for newly formed wind slabs on leeward slopes near ridge lines. Even though it didn't snow very much, 64-92 mph winds transported the little bit of snow available on to NW-E slopes.  In areas below 4,500 ft, wind slabs shouldn't be a concern.

Avalanche Problem 2: Persistent Slab
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There are 2 buried surface hoar layers in the snowpack to keep in mind. Nether layer has been very reactive yet... but, they're both capable of coming to life at some point. The rain falling outside is putting more weight on the snowpack which increasing the probability of triggering persistent layers.  In a couple days, after the snowpack has a chance to adjust to the new load, the stability should increase.  Be extra cautious on saturated steep slopes near and below treeline.

Avalanche Problem 3: Deep Slab
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The Thanksgiving crust is still down there! At this point, it would be difficult to trigger a slide on it... but not impossible. The most likely scenario would be a avalanche higher in the snowpack stepping down to that layer. It's not the biggest concern in the snowpack but we have to remember it's there and capable of producing large and destructive avalanches.

Weather and CURRENT CONDITIONS
Weather observations from the Region
0600 temperature: 21 deg. F.
Max. temperature in the last 24 hours: 33 deg. F.
Average wind direction during the last 24 hours: W
Average wind speed during the last 24 hours: 30 mph
Maximum wind gust in the last 24 hours: 92 mph
New snowfall in the last 24 hours: 1-2'' inches
Total snow depth: 109 cm inches
Two-Day Mountain Weather Forecast Produced in partnership with the Spokane NWS
For 2000 ft. to 4000 ft.
Tuesday Tuesday Night Wednesday
Weather: Cloudy / Showers Rain / Snow Slight chance of snow
Temperatures: 39 deg. F. 28 deg. F. 34 deg. F.
Wind Direction: SW SW SW
Wind Speed: 8-11 7-9 6-8
Expected snowfall: 0 in. >1'' in. >1'' in.
For 4000 ft. to 6000 ft.
Tuesday Tuesday Night Wednesday
Weather: Snow showers Chance of snow Chance of snow
Temperatures: 29 deg. F. 21 deg. F. 28 deg. F.
Wind Direction: SW SW SW
Wind Speed: 22-24 24-26 10-12
Expected snowfall: >1'' in. >1'' in. >1'' 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.