The New and improved Oregon 2020/2021 Ski Season Thread

[::: :::]

MHM closed tomorrow for weather

[thefortrees]

Funky? Do you have observations indicating possibility of persistent slab problems on N facing terrain in the Hood zone? Why do you feel a high SWE loading event is beneficial for the stability of the snowpack?

Was on a NW aspect @ 6k on Saturday. Found three obvious crusts, ~20cm, 50cm and 80cm. ECT gave results that we did not expect and changed our plan for the day. ECTP 27-Q1 on the first crust. Surprised at how clean the shear was, so kept going... ECTP 21-Q1 on the second crust. ECTP 23-Q1 on the third crust. You sound like an avalanche expert, so correct me if wrong: seems like a recipe for a large slide if you trigger one. Significant rain = warming of snowpack = bonding of all layers as it refreezes

[CnRzG]

Knowledge is power.

[Toadman]

Sadly, your numbers are softballed. Read the NOAA Flood Watch details ... current forecast is that this AR could drop 4-8” of rain between tonight and Weds morning.

Where's that damn polar vortex when you need it!?

https://www.usatoday.com/story/news/...us/6623574002/

[Supermoon]

As a PSA while we wait for more favorable conditions, the Maggot Photo Contest has rebooted, and submissions are open. Lots of good shots in here that could be entered...

https://www.tetongravity.com/forums/...-Feb-28th-2020

[jonesy]

Super day @ the bachelor today. Sweet conditions & low lines. Nice wind transport snow pockets on Sunrise & CC area. Laid down trenches with my TT 80s. Had a few beers, it's all good.

[thefortrees]

Glad to see somebody was actually skiing today!

[jonesy]

Tbs had a appointment with his Parole officer in the Witness Protection Program otherwise he would of made it.

[river59]

Ghost town and fast firm conditions at MHM today. Felt really nice to let the superbros run free.

Dust off the PVC tuxedos!

[Hood26]

T Line, Ski Bowl, and MHM closed tomorrow.

[homeeey]

Was a good one today. Sunny weekends on the hill scare me more than most natural occurring things, but I once again made it out of there in one piece. Just leave the jacket unzipped an let it rip

the day hikers who made it half way up the face and the sledding taking place at the meadows turn off/roundabout are showing this season has legs

I was on MHX directly above the hikers as the MHM host road up to tell them what was up. Were you solo riding Nordicas?

[klauss]

Would have been a lot cooler if they were extreme sledders, but impressed they made it up that high as their route was right under the lift.

Not me on the Nordicas.

[Hood26]

Would have been a lot cooler if they were extreme sledders, but impressed they made it up that high as their route was right under the lift.

Not me on the Nordicas.

Did you see them walking up? I never did. Maybe they came in from the Mirror Lake trail? I could see it being a beat in track by now with the lack of snow.

[klauss]

I’m discussing the hikers walking up mount hood meadows face and their path was right under the Mt hood express chair. Probably just eager to reach the summit in their leather hiking boots, jeans, and bugaboo jackets. They were definitely getting heckled from the chair but were resilient.

[Hood26]

I’m discussing the hikers walking up mount hood meadows face and their path was right under the Mt hood express chair. Probably just eager to reach the summit in their leather hiking boots, jeans, and bugaboo jackets. They were definitely getting heckled from the chair but were resilient.

Oh damn there were all kinds of fun hikers out this week. Sorry for not keeping up. Have a good one.

[SchralphMacchio]

You sound like an avalanche expert

I'm not, I've only spent little bits of time around a few people I'd consider as such, and I want to apologize for any dick measuring intentions or implications in how I phrased my questions in my post.
Because in the big picture - it isn't most important to be able to drop a bunch of acronyms, or whether you consider yourself or others consider you an avalanche expert ...

I've adopted the current mantra of the AIARE Risk Management Framework in saying that what's most important when skiing in the backcountry is recognizing the uncertainty you have about all the variables in front of you, the team, the snow, the stability, weather, terrain, navigation etc, acknowledging what you don't really know, and being able to say if the specific consequences of fucking up are beyond what you can tolerate given that uncertainty. I'm saying this for the benefit of anyone whose ears perked up when they saw my question and your response, because the third part of this post is less important to good decision making than first two bits. Also saying this because the AIARE Recreational curricula have really evolved over the last 5-6 years and for anyone who hasn't refreshed their training in a long while, it's well worth it to just re-take the Rec 1 and Rec 2 courses.

ECT gave results that we did not expect and changed our plan for the day.

In light of my comment above, props for having a plan, taking observations, and changing the plan to be more conservative when expectations weren't met.
Seems basic but I run into so many people in the backcountry who do none of this ... sigh.



With all that out of the way ...

Found three obvious crusts, ~20cm, 50cm and 80cm ... Surprised at how clean the shear was ... ECTP 23-Q1 on the third crust ... seems like a recipe for a large slide if you trigger one.

Yeah my main question was did you have reason to think persistent slab problems were possible, and your answer above is hell yes!

The easy way I see to look at this is that you directly observed propagation potential behavior on a crust that was capped by two other crusts ... something deep enough and old enough (propagation potential persisted through at least two subsequent loading events) that you could call it persistent. Easy. Persistent slab 80 cm big is scary, basically unsurvivable in most types of terrain, large propagation potential, and doesn't heal quickly. Who knows the distribution? Who knows if it will persist beyond this week? With persistent slabs keep the uncertainty high regardless of what weather comes in.

The more complicated way I look at this, I was specifically looking to hear whether you observed any faceted forms like surface hoar or near crust facets, or if you suspected such forms were possible/probable/likely given the weather history in that area. You didn't state anything about grain forms at that 3rd crust, so at risk of presuming nothing was obvious I'll offer an unsolicited tip (apologies in advance if its not welcome), next time you get a shear like that, *especially* if your column fails via sudden collapse rather than sudden planar, lightly scrape your hand and/or a grain card above and below these crusts to see if you can find any obvious or less than obvious angular / cane-sugar / ziggurat like forms. Seeing that would be a major, major red flag to be super cautious about terrain choice.

The key now is to keep that persistent slab on your problem list, and go looking for that interface after this next loading round and set of weather changes to see if you can determine whether the propagation potential is essentially staying the same, getting worse / easier to trigger, or getting more stubborn, or best case you can't really find or identify it anymore, then figure out when you have enough certainty to mess with it on given terrain with given consequences.

Significant rain = warming of snowpack = bonding of all layers as it refreezes

I thought I learned in Avy 1 course that rain percolates through the snowpack consolidating the layers. Correct me if I am wrong. ( I realize it can also make the load heavier and trigger big huge wet slides too.)

Rain can be a double edged sword and we can probably debate over several beers / pitchers / cups of tea for the abstinent about when heavy rain above pass elevations is "needed" or "a good thing." From a stability perspective the big downside to rain, especially early and midseason rain, is what happens *after* it falls ... what happens if it gets really f'ing cold? If the saturated snow and free water on the surface freezes solid you get a thick heavy ice lens that acts as a temperature reservoir and source of water vapor pressure. Then what happens if it only snows a few inches of cold snow on top of that rain crust? What can happen if air temp gets cold and/or clear after that shallow snow falls? The temperature and vapor pressure gradient above (and sometimes below) that rain crust can form near crust facets (NCF) that don't easily heal with subsequent loading and give a veiled indication of strength while actually having shit structure with massive propagation potential. Even in coastal mountains NCFs that create persistent slab problems can actually make for a season long problem that could continue to build up and up into super scary desctructive potential, just ask longtime Baker skiers what they think of raincrust driven NCF interfaces. I believe that later in the season stout rain crusts can also serve as glide layers where free water is unable to percolate below them, so again massive wet slab potential during a melt event of the upper snowpack.

So yes, rain means warming of the snowpack, it means added weight to test any weak layers that might be on the verge of failing, it could mean percolation of free water through various layers. I've even once seen where copious amounts of rain percolated to basal facets formed on the ground and literally froze them into place and turned a persistent slab problem into a melt-freeze snowpack (zero to hero, yay!). But rain is not always *necessary* to resolve a weak interface. Extended periods of near-freezing / warm temperatures are generally what resolves weak interfaces ... and it can do it without washing away precious snow near or below pass elevations.

Granted, so far this season we've been in very warm cycles overall. I haven't been keeping too much attention east of the crest and north of 20, but it just seems like the pattern has been staying warm enough following precip cycles that odds of NCF setup are lower. But like I said, uncertainty.

I agree with the Toadman.. Consolidate that snowpack and make it as dense as possible for a long spring.

In my view ... warm spackle snow and a lot of it makes a dense consolidated snowpack that makes a long spring; rain at high elevations melts the snow you were hoping to skin on come Father's Day and 4th of July and instead makes for a longer walk in approach shoes. Although like I did say before, a good mega avalanche cycle followed by reloading of the snowpack can bring dense snow further down into slide runouts that make for possible late season skiing lower down before you're back walking on dirt and rocks (if that slide runout hasn't been suncupped to hell by then).

[CnRzG]

Thank you for that lesson. I mean that with all sincerity and not a lick of sarcasm. Respect.

[::: :::]

(I need to refresh my avy I)

[jonesy]

Good educational read.

[Norseman]

solid dump, shralph

[thefortrees]

Nice information, thanks. Wasn't trying to be sarcastic, genuinely was looking for your thoughts.

[SchralphMacchio]

I didn’t assume you were being sarcastic, it’s just that “expert” is a bit of a trigger word when it comes to avalanches as you don’t need to be one to make good decisions, and snow science alone doesn’t teach you to make better decisions. Also I was being a little bit of dick in how I phrased my original question - and we’ve never met - which is why I went out of my way to settle that.

I’m also not a certified instructor or pro observer. I have friends in or formerly with the AIARE organization and am pretty up to date on the current curricula which is why I’ve mentioned that it’s worth retaking or refreshing the Rec L1 and Rec L2 if it’s been a while. I’m hoping once my kids are older I’ll have time to get instructor certified and spend more time out in wild places in the snow ... dreams!

[jonesy]

As a Meteorologist in a former career this is a fascinating Snow Science. That's as far as I want to experience it. Thanks again for the knowledgeable insight.

[SchralphMacchio]

Jonesy I need to share some chairs with you at the Doo this season. Got your number from TBS. I’d love to talk mountain weather some time! And just as well could probably use a couple private lessons to get out of the back seat lol.

[jonesy]

I look forward to meeting you and weather related discussions. Please contact me anytime you head to the Doo. I'll make a point to be there. I'm sure your technique is impeccable and beyond reproach.