[gb]

NWAC issued a special bulletin this afternoon. Recent snowfall is up to 15" or so many places above 5000' or so. Even Washington Pass should have upwards of 6" new snow. I'm sure it wasn't all that settled even before this as we had been getting 2-3" a day for a few days before this. Now, the freezing level is expected to rise for the next several days. As it rises, the recent snows and even some older snow will be stressed and continue to be stressed as the freezing level continues to rise - all the way to 12000' - 13000' by the early part of next week. There may not even be an overnight freeze by the middle of the weekend. It will become more stable once freezing levels begin to drop mid-week next week.

[AlpineRose]

Big snowfalls this late in the year are just.not.a.good.idea. All the consolidation, corning up stuff just gets delayed that much more.

[DIYSteve]

Yup. New snow on top of dirty snow followed by sun and warm temps = slide potential. 2-3 inches might set up hissers. More than that could set up bigger wet slides. A guy could get buried in a terrain trap.

[pipedream]

Observed evidence of a few wet, loose slides this morning triggered by snowfall off cliff bands in the Alpental valley. Heard them, too. It should be a good weekend for watching things slide from safe viewpoints (Lake Serene, Big 4 Ice Caves Trail, etc.)

[DIYSteve]

pipedream sighting on NWHikers!

[trestle]

Is the early-season PWL still observable?

[pipedream]

It doesn't seem to be. I would imagine it was crushed under this winter's hearty snowpack and any lingering ice crusts from our numerous freezing rain events in the passes should be gone as well. The big concern at the moment is the significant daily warming and lack of sufficient overnight cooling leading to wet loose instabilities, cornice collapse potential and the low probability / high consequence of wet slab releases on smooth underlying surfaces (e.g. lubricated rock).

[AlpineRose]

As well, while the more athletic among us sometimes manage to ride out of mid-winter powdery moving snow, once you are entrained in late spring's incredibly heavy, incredibly incohesive slides, you will be going where the snow is going.

[gb]

The NWAC updated the Avalanche Forecast for the period of this weekend (even current) through Tuesday or Wednesday of next week. Hint: Read the "Discussion". Avalanche Forecast This is not your garden variety spring diurnal avalanche cycle. Satellite and temperature data probably indicate an overnight freeze last night at Paradise - but lots of new snow - but Baker this morning was 6F warmer than the night before and is already at 5am 10F higher than the day before. Probably only a few clear hours overnight in the north. Friday night it looks cloudy and probably party cloudy Saturday night - not much of a freeze - then it hits a fan Sunday as freezing levels rise another 3000' and the sun comes out to toast the snow. It would probably be interesting to watch the activity on especially higher peaks like Shuksan, Sahale, Johannesburg, and the slopes of Van Trump Park particularly on Sunday. But there could still be plenty of activity Friday - Saturday with all the recent snow

[cartman]

This weekend has a high potential to be bad, and with the good weather and increased access almost a guarantee that SAR is going to be busy. For example, I know of four nwhikers going into the Washington Pass area to do Straight Ridge, 7700', from the south, on Sunday, despite every warning and caution I can throw at them. Including the NWAC Advisory and these threads on nwhikers. Because, you know, it's OK to risk your asses like that when you have kids and SAR might have to risk theirs to bail you out. After all, the highway is open now so we just have to push it to the max right away. Maybe the chutes will release on Saturday and close the highway and make it all moot.

[cartman]

From NWAC Observations page: May 18, 2017, 3:33 p.m. PST Region: East Slopes North - Canadian Border to Lake Chelan Observation by Huginn , Muninn , Geri , Freki ,Odin , SKIER-X Did you see any avalanches? Yes Did you trigger any avalanches? No (actually Yes, see below) Was anyone caught in an avalanche? No Area Description: Liberty Bell west S.R. 20 , N.C.H. Route Description: SW X NW aspect 5400 -7200" Weather: Mostly sunny 50 deg. wind variable . Pleasant Snowpack: 1/4" wet corn rounds on 1 1/2" humid transforming settling storm snow on 1-2" softening granular supportive base. Clean in openings , drip rings in trees , but soft . Avalanches: Wide spread storm snow releases , both natural and skier triggered on all aspects at about 30 deg. or steeper from Yesterday and today. Sun exposed aspects released snow and rotting ice fall today and yesterday propagating point triggered releases below warming rock faces

[gb]

Baker telemetry showed that it got down to 43 degrees at 5000' by 9pm last night, so probably a freeze, but temperatures warmed all night to the low 50's by 5 am. It will likely warm rapidly today with avalanches at higher elevations becoming more likely. Since the telemetry at Baker is on top of the mountain, it is indicative of free air and ridge top temperatures. The only good freezes are likely to be in flattish and locally lower areas and bowls where cool air collects. The high freezing levels probably indicate no freezing tonight through Monday night and still very warm daytime temperatures in the mountains through Tuesday. With the warming, somewhat deeper layers could be involved in avalanches beginning this afternoon and continuing through Tuesday. Then, much cooler. Incidentally, it appeared mostly cloudy along and east of the crest yesterday with build-ups and numerous showers visible from the eastern shrub steppe yesterday. Those showers probably were well into the mountains.

[Bootpathguy]

[gb]

I misquoted the telemetry - but not the scenario. that was actually Paradise. Baker was 47 degrees last evening and warmed to 55 by 5 am and then 64 by 7 am....

[mountainsandsound]

I was with friends Satuday in the Snowking area south of Cascade River road. We had mostly sunny weather with an afternoon that got very warm. From afar we saw plenty of large, loose avalanche fans and debris that had released before our arrival and some glide cracks on polished rock faces. Our party triggered some small and limited loose wet avalanches in inconsequential terrain.