THIS AVALANCHE ADVISORY EXPIRED ON February 7, 2018 @ 7:04 am
Avalanche Advisory published on February 6, 2018 @ 7:04 am
Issued by Melissa Hendrickson - Idaho Panhandle Avalanche Center

St. Regis Basin/Silver Valley

bottom line

The recent precipitation pattern has injected a lot of heat into the snowpack (here) accompanied by average air temperatues being above freezing for the last four days has led to an unstable snowpack. Overnight loading of an additional 0.5 to 1" of snow water equivalent (3 to 7" of snow) has further destabilized the pack. It is important to pay attention to these spring like conditions and not become complacent because the snowpack is stable at lower elevations.  

How to read the advisory

St. Regis Basin/Silver Valley

How to read the advisory

The recent precipitation pattern has injected a lot of heat into the snowpack (here) accompanied by average air temperatues being above freezing for the last four days has led to an unstable snowpack. Overnight loading of an additional 0.5 to 1" of snow water equivalent (3 to 7" of snow) has further destabilized the pack. It is important to pay attention to these spring like conditions and not become complacent because the snowpack is stable at lower elevations.  

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.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Storm Slab
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Overnight 3-7" of dense snow blanketed the region adding yet another storm slab to the high elevations on top of already heavy, wet storm slabs.  Snow/rain levels have been inconsistent this week, so as you are travelling, stop and observe the changes in the snowpack as you gain elevation and how the new snow is bonding. 

Avalanche Problem 2: Wind Slab
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Transport speed winds and avaliable snow for transport have created large windslabs on lee terrain in the high elevations.  Wind direction is changing from yesterday, so expect windslabs on multiple aspects

Avalanche Problem 3: Persistent Slab
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There are still crusts and associated weak layers throughout the advisory area that backcountry users need to be mindful of. The only way to be certain they aren't where you are recreating is to dig down into the snowpack and assess at each location.  As they continue to get buried deeper, the probability of triggering becomes less, but the consequence becomes higher. 

recent observations

Reports from the region yesterday incluced two human triggered wet slides. Thank you Silver Mountain Ski Patrol for helping with observations this week.   

Feel free to send me your observations as you get our into our backcountry. All information is helpful. Send them to mrhendrickson@fs.fed.us or use the observation button on the left.  Reports can be kept anonymous. 

Weather and CURRENT CONDITIONS
Weather observations from the Region
0600 temperature: 28 deg. F.
Max. temperature in the last 24 hours: 29 deg. F.
Average wind direction during the last 24 hours: NNW
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 25 mph
New snowfall in the last 24 hours: 3-7 inches
Total snow depth: 65 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Spokane NWS
For 2000 ft. to 4000 ft.
Tuesday Tuesday Night Wednesday
Weather: Areas of Fog then cloudy slight chance rain/snow then rain/snow likely Chance rain/snow then chance rain
Temperatures: 36 deg. F. 35 deg. F. 42 deg. F.
Wind Direction: SW SW SW
Wind Speed: 7 6-9 9
Expected snowfall: 0 in. <1 in. 0 in.
For 4000 ft. to 6000 ft.
Tuesday Tuesday Night Wednesday
Weather: Snow likely then chance snow and breezy Snow and Windy Snow and Windy then Rain/Snow Likely and breezy
Temperatures: 31 deg. F. 31 deg. F. 36 deg. F.
Wind Direction: West SW SW
Wind Speed: 17-21 (G29) 24-30 (G41) 21-25 (G36)
Expected snowfall: <1" in. 2-4 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.