THIS AVALANCHE ADVISORY EXPIRED ON April 7, 2018 @ 6:54 am
Avalanche Advisory published on April 6, 2018 @ 6:54 am
Issued by Melissa Hendrickson - Idaho Panhandle Avalanche Center

St. Regis Basin/Silver Valley

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Continuing with our April snow showers theme through Friday, we recieved 2 to 7" of snow in the last 24 hours at the high elevations.  This came in warm yesterday and had good bonding to the crusts underneath, but expect wind slabs at the ridgelines from the cooler snow that came in overnight.  Cold overnight temperatures helped improve the stability due to wet slide potential, but watch for it to increase as daytime temperatures go above freezing again this weekend.

How to read the advisory

St. Regis Basin/Silver Valley

How to read the advisory

Continuing with our April snow showers theme through Friday, we recieved 2 to 7" of snow in the last 24 hours at the high elevations.  This came in warm yesterday and had good bonding to the crusts underneath, but expect wind slabs at the ridgelines from the cooler snow that came in overnight.  Cold overnight temperatures helped improve the stability due to wet slide potential, but watch for it to increase as daytime temperatures go above freezing again this weekend.

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: Loose Wet
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Temperatures hovering right around the freezing mark deliveried a new snow layer with a lot of moisture in it yesterday afternoon and into the night.  The higher elevations cooled down overnight, but mid elevations and below stayed right around freeezing.  Expect the higher elevations to warm up during daytime temperatures that are above freezing or with rain as we move through the weekend. 

Avalanche Problem 2: Wind Slab
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Temperatures dropped overnight and deposited new, cooler snow at the ridgetops and ridgelines.  Expect to find small wind slabs on leeward slopes.  The winds are predicted to shift direction with the storm coming through, so make sure to check the ridges to see if there are small windslabs on directions you usually don't expect.  

recent observations

We travelled to the Mullan Pass area and the FAA dome above Lookout Pass on Thursday.  The rain line was around 5500ft and the snow up to 6100ft was very wet and dense.  Pinwheels were prevalent on all aspects yesterday; the surface layer of snow had a lot of trapped moisture.  The positive side of this snow being so heavy and dense is that it has bonded very well to the crust layers underneath.  Overnight, the temperatures cooled and transitioned into lighter snow on top of this at the highest elevations.  Yesterday the wind slabs and the persistent weak layers weren't being reactive in pit tests.  Great skiing, albeit a little sticky. 

This is the last regular Friday forecast for the season.  We have a great snowpack headed into spring skiing, so there is still lots of good riding and sliding to be had.  When you are planning your backcountry travel, use normal avalanche caution. As the mercury rises, watch for wet slides. Spring is a game of temperatures, plan your tours to work with that. Keep your heads up for cornices above you. As they get heavier and denser from rain, the risk from them falling increases. There are still several persistent buried weak layers down there on the northerly high elevations. They haven't been reactive in pit tests for us for a while, but they always have a potential to wake up and become reactive with more weight in the snowpack.  Just because it is spring doesn't mean to abandon digging pits.  Check out the snow before you commit to ride anything consequential.  And lastly, the way April has been behaving so far, we might not be done getting new snow. Treat those storms with your same winter caution until they have time to stabilize.  Enjoy the long spring ahead of us and see you next season!

Weather and CURRENT CONDITIONS
Weather observations from the Region
0600 temperature: 19 deg. F.
Max. temperature in the last 24 hours: 34 deg. F.
Average wind direction during the last 24 hours: ESE
Average wind speed during the last 24 hours: 7 mph
Maximum wind gust in the last 24 hours: 11 mph
New snowfall in the last 24 hours: 4 inches
Total snow depth: 82 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Spokane NWS
For 2000 ft. to 4000 ft.
Friday Friday Night Saturday
Weather: showers likely then mostly cloudy mostly cloudy then rain likely Showers and Breezy
Temperatures: 41 deg. F. 36 deg. F. 45 deg. F.
Wind Direction: E E NE
Wind Speed: 5-13 7-11 13-21 (G32)
Expected snowfall: <.5 in. 0 in. 0 in.
For 4000 ft. to 6000 ft.
Friday Friday Night Saturday
Weather: Snow then chance snow chance snow rain/snow and breezy
Temperatures: 33 deg. F. 31 deg. F. 38 deg. F.
Wind Direction: SE E SE
Wind Speed: 7-16 7-15 13-22 (G33)
Expected snowfall: <1 in. <.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.