Avalanche Advisory

Issued: Thursday, January 11, 2018 7:00 AM Forecaster: Victor McNeil

Primary Problem

Secondary Problem


BOTTOM LINE:

Travel in avalanche terrain is not recommended today. Natural avalanches are likely and human triggered avalanches are very likely. A strong warm front will be pushing into our area today depositing 6-12" of snow followed by moderate (17-25 MPH) to strong (26-38) winds from the SW. Our current snowpack, with it's poor structure will likely be overcome by this heavy new load. Natural activity was reported in numerous location yesterday in the Southern Wallowas, meaning the stress to strength ratio is already in flux. Expect wind slabs above tree line on NE-N-E aspects up to 2' or more by Friday. If you trigger a wind slab it could step down to our Thanksgiving Day crust/facet weak layer and produce a large avalanche. Remember the deeper the Thanksgiving Day weak layer gets buried the larger the potential avalanche and we won't see Red Flags from this buried weak layer.

SPECIAL ANNOUNCEMENT:

A big thanks to the Tollgate Trail Finders Snowmobile club who invited the WAC to their clubhouse last weekend for an Avalanche Awareness Presentation and Companion Rescue Clinic in the field. We had 7 riders in the field and practiced fundamental beacon skills, probing and shoveling and worked through a multi burial rescue scenario. You can visit their website here: www.tollgatetrailfinders.org. The Eastern Oregon Backcountry Festival takes place January 19-21st and is a great way to get involved with the local Wallowa Avalanche Center and help support a great organization. The Festival will take place over three days and will include a showing of TGR's "Rogue Elements" Friday night in La Grande accompanied with a fundraiser. We have some phenomenal raffle and auction items including: BCA Rescue Package, Dynafit Bindings, BCA Airbag Pack, Black Diamond gear, Da Kine goodies, Scenic Flight through Wallowas and more. Check out the following link for more details: https://www.eou.edu/outdoor/eastern-oregon-backcountry-festival-2018/ You can email Michael Hatch for more details or questions at mhatch.eou.edu

Recent Activity

I received a report from the Southern Wallowa's (near Norway Basin) yesterday of Natural Avalanche Activity on E aspects above 7,000' in two locations near ridge lines. There was also a report from a snowmobiler in Little Eagle Meadow who experienced natural avalanche activity. When we start to see natural avalanche activity that's a good indicator the avalanche danger is HIGH. With a significant storm passing through today expect to see more natural avalanche activity. Please send us your reports if your observe Red Flags or avalanche activity.

Current Conditions

As of 4am skies are overcast and snow is falling. In the Blue Mountains the High Ridge Snotel was reporting 30 degrees and 23" of snow. Anthony Lakes ski area was 23 degrees with 53" and winds were not registering. In the Northern Wallowas the Aneroid Snotel was showing 27 degrees with 16" of snow. Mt Howard was 24 degrees and winds were blowing from the WSW at 13 MPH. In the Southern Wallowas it was 28 degrees with 27 inches of snow. Overnight we've picked up a couple inches of snowfall at most locations. In the past week we've had close to 1' of snow above 7,000'. Today we are expecting to see a moist warm front pass through, with 6-12" of snow forecasted above 7,000' and moderate to strong winds in the Northern Wallowas and Elkhorns. Snow levels will remain below 5,000' while temperatures will fluctuate close to the freezing line. Friday will see lingering snow showers, but nothing significant and winds will decrease.


Avalanche Problem #1

ASSESSMENT
Winds will be moderate to strong through today, predominately from the SW. There's already light density snow available for transport and with the additional 6-12" expected today wind slabs could be 2' deep or greater on leeward aspects (NE-E-N). If you trigger a wind slab there's a chance you might react the Thanksgiving Day crust buried down 2+ feet. Use extreme caution on or around wind loaded terrain >30 degrees. Wind slabs will often feel drum like and hollow underneath. With the moderate/strong winds, expect wind slabs further down slope than otherwise expected.
TREND

Increasing over next 48 hours
LIKELIHOOD

SIZE

Avalanche Problem #2

ASSESSMENT
Our persistent slab problem, being the Thanksgiving Day crust with sugar snow above it, is now buried 2+ feet above 7,000' in most locations. This layer is becoming more difficult to trigger in stability tests and is not giving us Red Flag warnings. To realize failure on this layer we need a bigger load and we are going to see that today. Possible locations to trigger this layer include trees, rocks and other shallow areas. This nasty weak layer could remain in our snowpack for weeks or months and when it rears its ugly head we'll see some big avalanches.
TREND

Increasing over next 24 hours
LIKELIHOOD

SIZE

Mountain Weather


        
                
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General Annoucement

Victor McNeil will issue the next Advisory Saturday January 13th at 7am.


DISCLAIMER: This advisory does not apply to developed ski areas and avalanche terrain affecting highways.