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Posted

My climbing partner (masternate32) and myself, wanted to get away from school today and do some climbing, but the weather and avalanche outlook wasn't looking good at all. So, we decided to head to Guye Peak. Our plan was to do the South Rib. We got there and began postholing through snow up through the trees, then to some mildly open slopes in which we saw some shooting cracks in the snow. Oh, I should mention that it is raining fairly hard too. So we head up to the south side of the mountain and start going up, we were on snow for most of the ways, until higher. there was one rock section we did lower down, it was more like climbing a waterfall. We made it to this one rock section, just to the left of the south gully about half way up the ridge. I don't think we were on the rib proper, probably on the spur or something; we just went upwards. Well, it was raining and hailing and the rock was soaking, not very enjoyable and we couldn't friction on the rock, so we descended. We learned why you don't climb when it is raining hard. Still had a good time though, glad to get away for a short day. thumbs_up.gif, definitly will be going back this spring/summer on a nice day.

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Posted

Yeah, we were definilty concerneed about the shooting cracks, but it looked alright, plus we tryed to stay in the trees. also the forecast said most of the stuff in the lower elevations had already slid, so we weren't overly concerned, but we didn't waste our time in the avy prone areas.

Posted
Dru said:

when it does avalanche in the trees, and you get carried into tree well and buried, must be extra special suck way of dying.

 

or when it just avalanches from high above you and carries you into a terrain trap (like a tree well) that would be so suck, you couldn't even match it with an industrial catch basin cleaner/vacum.

 

Posted
AlpinistAndrew said:

We got there and began postholing through snow up through the trees

 

Andrew - was this snow or was this slush? Are we talkin' like 90% water content up there?

Posted

Unfortunately, that may not be for quite some time. The forecast shows that the freezing level is going to drop back down, at least to about 3,500' by Saturday, so at least all this wet snow that's settling should solidify pretty nicely?

Posted

I'm trying to imagine exactly how there could be shooting cracks in the snow. You are referring to a slab like upper snow pack that is settling suddenly when your body weight stresses it? Granted there was a ton of snow last weekend, but hasn't it been raining buckets up there since? How is there a cohesive enough slab overlaying a weakness able propogate cracks at 3500ft?

 

Unless, the upper snowpack was dense, wet slab, the rain hadn't made it down to lower density snow deposited last week and the upper slab was failing on this lower density snow? I'm trying to further my own snowpack/avi understanding.

Posted
ski_photomatt said:

I'm trying to imagine exactly how there could be shooting cracks in the snow. You are referring to a slab like upper snow pack that is settling suddenly when your body weight stresses it? Granted there was a ton of snow last weekend, but hasn't it been raining buckets up there since? How is there a cohesive enough slab overlaying a weakness able propogate cracks at 3500ft?

 

Unless, the upper snowpack was dense, wet slab, the rain hadn't made it down to lower density snow deposited last week and the upper slab was failing on this lower density snow? I'm trying to further my own snowpack/avi understanding.

 

your unless was exactly what was happening in a lot of places. dense heavy wet slab over buried surface hoar layer = death on a stick.

Posted

I was just looking at telemetry data from Alpental. The snowdepth peaked Sunday afternoon at 95" before changing over to rain. By yesterday morning they had recorded nearly 5" of rain since Sunday and the snowdepth decreased to 69" (it looks like it was 54" or so early last week before it started snowing). AlpinistAndrew, were slabs cracking? How deep were they? What were they sliding on? We were out on Skyline Ridge above Stevens Pass last Saturday and found the new snow was sitting on a hard crust, our rutchblock failed just above the crust. All the new snow could have consolidated into a slab and be sliding on this crust. The part that gets me though, is I can't quite imagine a cohesive slab, or one cohesive enough to propogate cracks. I'm picturing something more like deep corn similar to afternoon snowpack on warm, spring days. Can slush propogate cracks?

 

Posted

top layer of hard slab can be slushy if rain is coming down too fast to infiltrate lower into the snowpack. sorry for getting technical, but its like why it can rain on hard pack dirt and a big puddle forms but if you dig under the puddle it will still be dry (also known as why the gophers don't drown) snaf.gif

Posted

dru,

 

based on a recent trip out my door, i can tell you its well saturated fairly far down with several days of steady rain although it's lovely now. There is still firm pack but it's well below the surface.

It could slide but i'd say the risk is of that dropped all week.

Posted

ok- fair point. Sorry i'm slightly out of it today.

 

It saturated pretty quickly b/c the dump we got last week was pretty fluffy. It was probably pretty similar then although not totally stable. Haven't noticed a lot of slides off the peak this week.

Posted

Dru, no need to apologize for getting technical. I'm trying to arrive at a technical answer. The cracks were noticed yesterday (Thursday). I purposefully dug up the telemetry data to hopefully show that the snow pack is most likely slush down quite far. It's has been raining since Sunday afternoon there, with 5" (127mm) of rain recorded by the sensor as of Thursday morning. For comparison, the average total January precipitation at SeaTac is 5.13" The snow pack depth had decreased an alarming 26" (66cm) since Sunday. This is not rain falling onto a hard slab and I think we can assume (even without Minx's firsthand confirmation) that the rain has percolated fairly far down, at least to the bottom of the snow from last weekend. What I can't figure out is how can a snowpack like this produce "shooting cracks"? Is there something I'm missing here? Can saturated, wet slab propagate cracks, even above a hard crust? Anyone who has skied in the spring has certainly kicked off slush and watched it slide, but I can't remember seeing the wet slab propagate a crack and then slide. Perhaps I'll pay more attention this spring. The area grows more by entraining snow at the sides then by cracking like a hard slab. It's been very windy this week, the winds have been predominantly southerly and likely hitting the open area below Guye's south rib. Does this matter?

Posted

its more about trying to figure out why what is reported happening, happened than trying to figure out if what was reported was BS or not... i dont know if there really are shooting cracks or what up there but if there were things could have settled down quite a bit in a few hours time... they were up there Monday? (Alp A correct me if Im wrong here) and it had only been warm for a day up there***, and its possible that, ice layers or whatever in the snowpack were preventing water from penetrating all the way down and a lower weak layer existed. the only way we'd really know was if they dug a pit which it sounds like they didnt do...

 

personally i think propagating cracks are a good excuse to go home and have a beer, then again i have never seen one cause i only go out when avvy hazard is LOW, other than that its cragging weather. cantfocus.giftongue.gif

 

 

***edited I just looked at it they were up on Wednesday I dunno what the hell they saw or why it occurred and i will shut up and play tetris.

Posted

Just to clear some stuff up. I went up with Alpinist Andrew on Guye. We saw some cracks up there but we had a hard time telling if they were older weaknesses in the snow base because they were melted out a bit or if they were new and had just melted out because it was raining so friggin much. Neither of us are avalanche experts so I can't really help y'all out on the technical aspects of the snowpack. All I know is once we saw these cracks we treid to stay where there was the best footing or hurried across any suspect areas.

Posted

In the spring, when the snowpack warms up, it starts creeping downhill in steeper areas. This causes the formation of "creep cracks" that sometimes look like miniature crevasses, usually near the top of a slope and below some type of terrain anchor or maybe at the bottom of a gully or something. I don't think this type of crack necessarily indicates the kind of snowpack instability that is likely to cause an avalanche, but they do show that the whole mass is sliding and, depending on where that whole mass is headed - whether it is sliding down into a flat bottomed bowl or over a cliff or whatever, the whole thing could let go and slide big. Might this be what you saw?

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