SEWS and Avy

[t_rutl]

Deciding a no go on the Coleman Headwall due a lovely avy forcast for the weekend, I'm tossing around the idea of taking a buddy up SEWS (couloir and/or the arete) for an intro "alpine" outing as an alternative to cragging. Having never climbed at WA Pass yet, is the Blue Lake TH approach threatened by slide terrain like the hairpin side?

 

Thanks in advance.

 

Troy

[rocketparrotlet]

Where do you get your avalanche forecasts from? I thought that NWAC stopped broadcasting this time of year...

[Bronco]

The approach slopes to the South Arete on SEWS are pretty benign and relatively safe from avalanche traffic.

[genepires]

blue lake TH is not threatened by avi hazard. But the trail does have some possibility, especially above treeline. There was a massive slide that came down through the trees 2 or 3 winters ago. Took out a portion of the trail and lots of very old trees. But that is a very rare event. Without being there, I would think that the blue lake trail is fairly safe right now, especially in the morning.

 

The SEWS coulior is south facing though. I would expect some sloughage coming down it though. If you would be making big post holes it in, I would stay out of it. Better for a clear night with a overcast day.

[Josh Lewis]

Where do you get your avalanche forecasts from? I thought that NWAC stopped broadcasting this time of year...

 

They do for the most part, but yesterday they gave a report:

 

…Major Spring avalanche cycle probable... along with generally increasing avalanche danger through Sunday…

 

Increasingly warm and mostly sunny weather Thursday and Friday should be followed by continued high freezing levels reaching near or above 10,000 feet over the weekend along with a chance of afternoon showers, mainly Sunday. This anticipated warm weather…with the highest sustained freezing levels this spring since appreciable snowfall was received in April…should produce a significant increase in the avalanche danger carrying through the weekend. Increasingly deep wet snow conditions should develop at progressively higher elevations and onto more shaded terrain as this warm weather continues.

 

Recent warming conditions over the past few days has already begun producing widespread natural wet snow avalanches, both loose and slab releases on most south facing terrain below about 5000 feet and at lower elevations on all aspects. Reports from control work efforts at Chinook Pass Wednesday indicated significant wet snow conditions and large entraining wet snow avalanches had reached to the ridgeline above 6000 feet, whereas earlier unstable conditions were generally from 5000 feet and lower. Both natural and easily ski triggered slides were entraining laterally and many reached the valley bottoms with large debris volumes. Some large natural wet loose slides have also been reported on south facing terrain on Skyline Ridge and Lichtenberg Mt near or just east of Stevens Pass, with such slides entraining much of the gradually weakening and melting snowpack and some involving mud and rocks. Another indicator of increasingly wet and rotten snow conditions stems from a road building operation on a north exposure around the 4000 ft level near Alpental that had to be terminated prematurely on Tuesday when the snowcat was unable to gain traction in the very wet, slushy snowpack.

 

As a result of this increasing potential for a significant spring avalanche cycle and potentially dangerous avalanche conditions on slopes not experiencing recent avalanche activity, back country travelers are urged to perform careful snowpack evaluation, cautious routefinding and conservative decision making during the increasingly warm and mostly sunny days ahead. Be especially aware if you start to posthole and sink into wet snow above the boot top, or if you encounter recent avalanche activity on similar slopes, increasing sunball activity, or smaller wet loose slides kicked off from traverses. Also be sure to avoid slopes beneath cornices as these may fail during the warm days ahead and trigger some larger slides on the slopes below. Be sure that the primary goal for your trip is a safe and fun outing rather than having to reach the summit during dangerous conditions.

[t_rutl]

thanks gentlemen. thats the info i'm looking for!

 

plan is a first light start up the couloir. if it's a post hole mess we'll bag it and head up the arete. if solid enough, up, down, then the arete.

 

mark - NWAC will do "special anouncements" as they see fit. there happens to be one up right now, but also just having general knowledge of past, present and future conditions goes a long way in making your own generalized assesment.

 

Past - a fair amount of recent snow

Present - consideraby high freezing level

Future - the same

 

that calls for a spring avy cycle especially on terrian that hasnt shed yet. ie, north facing aspects and higher elev's