General observations re Whistler Snowpack Jan 11 2009

[LeeLau]

There's too many threads about the Whistler snowpack. People are posting to the thread by Clownshoes started in January 2008 thinking that it's this year. Here's an attempt to start discussion about the snowpack stability this year. I'll ask for it to be moved to Slide Zone if necessary but sadly many people don't bother reading that forum.

SUMMARY:

In the Whistler Symphony area immediately outside resort boundaries, the facet layer seems to be present on all aspects. It is present even in areas where wind might have knocked it out. It is causing failure of the entire snowpack in some of the areas in the Whistler/Blackcomb resort boundaries when bombed. It is buried relatively deep so it is hard to imagine any rain/storm/wind or natural event which will get rid of it except for the entire snowpack melting.


Here's some observations from out trip to the "Symphony Ridge" area. At the outset, before you access that area it's a good idea to check in with Whistler patrol to report that you're going in. They'll let you know the route to cross their tenure to access the backcountry. I don't think this is a regulation; its more of a courtesy as far as I know. There is no restriction on accessing the backcountry.

We ambled up a ridgeline just outside ski area in the park towards Lesser Flute. Saw helibombing on Piccolo Ridge and also naturals on storm snow on Oboe at the usual start zone at the windaffected N ridge where there's usually small cornices. Flute and Lesser Flute has no tracks. Cornices forming on Flute but they're not very big - perhaps due to there being not much snow?




Found the facet layer at ground at our pit with snow depth of 210 - 215 cms on a windloaded NE facing slope with inconclusive failures of the facet layer.



Here is a closeup of the facets that are the big problem and are now being referred to as the Dec 6 layer. They are about 2mm in size. The facet layer is 10cms to 15cms in depth. The layer is at ground. At our location is is buried about 200 - 190cms below snow which means it is now very well insulated from any rain, snow or wind event which happens at snow surface. Unfortunately avalanche control in the resort shows that the facet layer is still reacting to control (ie bombs).

"Reacting" means avalanches of the entire snowpack essentially to ground.



Meanwhile another group on an avalanche course dug a pit also to ground with the facets at snow depth of 185cms or so on a W facing slope with failure of entire block on an easy on a compression test.



Here is the natural avalanche on Oboe with artificial bumped up contrast to show the slide



Meadowskipping gentle slopes back down the ridge. Something to get used to this season




Conclusions are:

1. There's not a lot of snow on the alpine

2. Facets at ground are present on very different aspects and are present even in the sub-alpine where one might have hoped that wind would have destroyed the facets.

3. Failure of the entire snowpack to ground is very variable - ie it's incredibly difficult to take even a poor guess at where large avalanches could occur

I'll add the full jargon observations here - notes by Sharon

We did a little tour out to the ridge between Symphony and Lesser Flute, the safe way to Garibaldi.

We talked to [Patrol forecaster] before we headed out and told her we would let her know what we saw. We didn't make it back in time to get back up to Dispatch so if you could forward this info to her that would be great!

We dug our pit at 12:15, at 1800m under cloudy skies, light wind, NE Facing 25 - 30 degree slope (short slope - had bench below it).
-2oC air temp, Foot Pen was mid thigh, ski pen was boot high.

Height of snow - 195cm
First 25cm -> FIST
Next 50cm -> 4Finger
Remaining 120cm -> 1F
Within the bottom 120cm was a 10-20cm more granular layer of 4F, we found 10-20cm of facets at the last 10cm before ground. facets were 2mm+ and didn't look like they were rounding/decomposing

On a compression test we had an resistant planar at CT(Hard) 23 30cm down. We did an extended column and the 30cm layer did not propogate. Shovel shear hard had the entire block fail at the facets.

There were 4 other Avi groups out. Another group dug a pit at about 1750m on a West facing slope, 195cm Height of snow, they had a sudden pop at the ground facet layer.

We saw a size 1-2 avalanche on the North/West face of Oboe during the day, it did not propogate down the slope very far. Failed at rocks on Oboe ridge at the typical start zone of shallow pack We also saw slides on the North face of Lesser Flute, they also did not propogate.

Lee is not optimistic. He looked pretty sad and said he's resigned to writing off the snowpack for this year.

[Eldo]

Thanks for the current info. Hoping against all odds that the situation will improve.

[axelkeitz]

Thanks man!

everybody be safe this year....

[LeeLau]

Side question:

I have very little experience with faceted Rockies-style snowpacks and guess I'm still in a bit of shock. What do you all do when your snowpack is like this?

[pechelman]

im very risk averse, and as such, i manage my terrain
if that means meadow skipping, then thats what it means.
thankfully, this season hasnt been all meadow skipping this year even with a sketchy pack in areas.

beyond that, its a balance between bridging vs overloading the pack, which I just dont always feel confident in assessing

[khyber.pass]

Thanks Lee. We haven't met but everyone I know knows you ;-)

I am also resigned to a terrible year. I can't imagine this healing with facets on the *ground*. The W/B press release also noted that even in slide areas that revealed the Dec6 crust the facets are getting snowed on instead of breaking down..

That said around Tahoe their faceted layer did seem to heal. Perhaps someone from Tahoe can comment on what is going on down there?

[Spiralmind]

thanks for the 2009 update.

[mntlion]

Side question:

I have very little experience with faceted Rockies-style snowpacks and guess I'm still in a bit of shock. What do you all do when your snowpack is like this?

from a banff avi thread as written by skibee:

It's coffee time in the Rockies:

Eveleyens has three fantastic locations to serve you in Banff.

The Wildflower Cafe on Bear street offers the hippies in town an organic and gluten free choice.

The Cozy Cave Bakery across the street offers the best in all sugar, butter and frosting all the time choices.

If you prefer the brand name options then Second cup and starbucks are also available to service your caffeine needs!!!

All the doggies in town should be well walked in a few days and be happy to be left at a home in Feb when things settle down.

High/high/high = coffee time folks!!!

[link1]

Thanks for the info on points West and East in Canada. Is this the same situation for the interior? Revelstoke and kicking horse in particular. Just about to pull the trigger on flights into Calgary for arrival January 22nd. Looking to do a couple of cat days or possibly a heli day, one day at kH and the rest at Revy. Wondering if a different destination may make more sense.

[powdork]

That said around Tahoe their faceted layer did seem to heal. Perhaps someone from Tahoe can comment on what is going on down there?

Good Karma. The warmth might have also been a contributing factor.
We do have a somewhat nasty layer on top right now in some places but it should be breaking down with the corn cycle we're in. The next storm will likely start wet and bond well to whatever is there anyway.

Come on down. Bring weed. We're out.

[powslut]

Side question:

I have very little experience with faceted Rockies-style snowpacks and guess I'm still in a bit of shock. What do you all do when your snowpack is like this?

Wait another ten years until the snowpack stabilizes out.

Resort skiing is great right now. I've had one of the best weeks of skiing I have ever had in my life at Lake Louise. Fortunately the patrol up there runs on the assumption that we are going to have a bad snowpack so they start stabilizing and ski cutting slopes right from the moment there is enough snow on them to slide down on a pair of skis. Because of this policy there is some decent terrain open up there. Not all terrain, but we have some half decent stuff open.

[alto]

Come on down. Bring weed. We're out.

Bullshit.



Time heals all...

[Keegan]

thanks for the 2009 update.

Indeed.
As shitty as the news is, it's nice to see a concise report.

[kidwoo]

That said around Tahoe their faceted layer did seem to heal. Perhaps someone from Tahoe can comment on what is going on down there?

It hasn't fully disappeared. There's still a shit layer down at ground level but everything above it is extremely stable.

There was a full on climax slide on an area off the lake on a northeast facing slope (dick's peak for you locs) that looks like it happened right after the christmas storms here. If that layer persists, anything that goes will go huge since all the newer stuff above it is pretty bomber and unlikely to move.



In the words of our esteemed forecasters.

Snowpits continue to reveal pockets of depth hoar in some areas that had snow cover before the December storms. The strength and distribution of this weak layer varies greatly across the forecast area and even across a slope. Right now avalanche activity remains unlikely on this layer due to strong well-bonded snow on top of the depth hoar that should have enough strength to hold itself up. The current weather should allow this weak layer to gain some strength before the next storm cycle.?

http://www.sierraavalanchecenter.org/advisory.php

[LeeLau]

Thanks for the info on points West and East in Canada. Is this the same situation for the interior? Revelstoke and kicking horse in particular. Just about to pull the trigger on flights into Calgary for arrival January 22nd. Looking to do a couple of cat days or possibly a heli day, one day at kH and the rest at Revy. Wondering if a different destination may make more sense.

I've confined my remarks to just the Whistler area so please do not extrapolate to anywhere else. See avalanche advisories through the CAA and see the thread entitled "Interior BC" for information on other areas.

[f2f]

Fortunately the patrol up there runs on the assumption that we are going to have a bad snowpack so they start stabilizing and ski cutting slopes right from the moment there is enough snow on them to slide down on a pair of skis.

will this be patrol-initiated then? i took the pic at the end of the very cold cycle in december and was wondering...

[Eldo]

...I've had one of the best weeks of skiing I have ever had in my life at Lake Louise. Fortunately the patrol up there runs on the assumption that we are going to have a bad snowpack so they start stabilizing and ski cutting slopes right from the moment there is enough snow on them to slide down on a pair of skis. Because of this policy there is some decent terrain open up there...

An excellent point. The combination of a low snowpack and very cold weather in Nov/Dec is highly unusual for Whistler but almost the norm for Louise. So the tactics that patrol use at each area during early season control work are probably very different.

At Louise and Sunshine there's even the time-honoured tradition of groups of dirt bag skiers going out to boot and ski pack steeps runs after early snowfalls - in exchange for a pass. I can't imagine that amount of work is done on the early season snowpack at WB.

[powslut]

will this be patrol-initiated then? i took the pic at the end of the very cold cycle in december and was wondering...

I'd assume so due to the ski cuts on the lookers left hand side. Usually they will bomb the hell out of it before they let patroller's in there to do any cutting.

[teamdirt]

Side question:

I have very little experience with faceted Rockies-style snowpacks and guess I'm still in a bit of shock. What do you all do when your snowpack is like this?

From my rockies experience: depth hoar does not leave until it melts out in the wake of summer. it may bridge if the snowpack experiences a melt freeze-then it will be stable until the bridge breaks down-otherwise the sleeping giant awaits...

time to hit the beach.

side note:-hortesman glacier and glacier chair are closed until this warm spell subsides-I suspect they are thinking even skied runs may slide with the increased weight of the snow and the current bridging breaking down.

[bakers_dozen]

will this be patrol-initiated then? i took the pic at the end of the very cold cycle in december and was wondering...

Yeah that would be controlled.

Was talking to a patroler the other day and he said they bombed ER5 and it slide to ground a couple of weeks ago and that it probably won't open this year, like last year. ER7 also slide to ground and is slowly reaccumulating... not sure if it's open yet either though.

[powder11]

I'd be wary of meadow skipping right now. Seems like the low-medium angle stuff is whats going big. I'm going to stick to in bounds terrain... maybe learn how to rail slide or something.

[karpiel]

Side question:

I have very little experience with faceted Rockies-style snowpacks and guess I'm still in a bit of shock. What do you all do when your snowpack is like this?

Drink.


1234123123412341

[GoNads]

I'm going to stick to in bounds terrain... maybe learn how to rail slide or something.

Funny you should mention that... I tried "tricks" for the first time today in the park, as opposed to just straight airing everything for SX training for a change. If its possible, my truck is a 2-stroke. BRAAAAAAAAAP!

Its actually fun, I probably looked like a complete tool, and definitely overshot a few tables. Can't really justify it when I can go sledding, or ski fresh pow at resort, but its just too dangerous right now.

[paulster2626]

Perhaps this will help things out a bit?

Tonight..Extensive valley cloud otherwise a few clouds.
Alpine temperature increasing to plus 6.
Freezing level 3000 metres.
Mountain top winds northwest 20 km/h.
Wednesday..Extensive valley cloud otherwise Sunny.
Alpine high plus 9.
Freezing level 3000 metres.
Mountain top winds northwest 15 to 20 km/h.

Extended forecast for Whistler - Blackcomb.
Thursday.. A mix of sun and cloud.
Freezing level 2700 metres.
Friday.. A mix of sun and cloud.
Freezing level 2500 metres.
Saturday.. Sunny.
Freezing level 3000 metres.

[LeeLau]

Warming trend hopefully causing climax avalanches? I hope so

Some more observations - from duffy and Whistler area

Recent postings from Coastalex:

I spent the weekend in Marriot Basin. Not much snow there for this time of year. The trail is definitely skiable, but coming down through the forest is a bit rough at the lower elevations with logs and other debris feelable under the skis. Higher up the meadows still have alder standing. First meadow has about 1m of snow.

At the cabins elevation (1800m East Aspect) had a look into the snow. About 1.2m of snow depth. A laminate of 4f facets and decomposing ice crusts makes up the bottom 20-30cm. Above is a 1m slab of P-F density snow. Got a Moderate Compression Test (CTM) on the Facets, and an Easy Compression Test (CTE) in the new snow -30 cm down from the surface. Both fractured nice and clean (SP).The usual story.... A bit wind effected on the surface at this and higher elevations. Air temperatures where around -3.

The only recent (with the last few days) avalanche activity we saw in the upper valley was the slope above the cabin. A large slab probably released last storm in steep rock terrain. Crown was deep, to the Dec 6 crust. Also, debris was visible under the S aspects above the 1st lake, but no crown line where visible.

Traveled in ways to avoid much exposure to even the bottoms of slide paths, basically very conservatively. Skiing quality was good at Tree Line out of wind effect.

As I was skiing out to the car I started to think things are stabilizing a bit, BUT as we came out of the trees onto the logging road there was the result of a new Class 3 that had pulled out from the East aspect slopes above. Must have happened after the previous nights snow – there was no new snow on the debris or on the forest foliage that it had shaken. Crow ran 450m across the slope releasing 3 separate start zones at elevations from 1800-2000m. Crowns depth was 1-3m. This slide ran full path to below the road. What I found spooky was it only snowed 2-3 cm, with light winds the night this slide released. The slope must have been just primed to go.

Dave Sarkany

Ski Guide

Was in the area of Oboe/Singing Pass today (090110) with clients. The alpine has seen considerable wind effect in the last 36 hours. 20 cms of 1 finger resistance over lies about 1m of consolidated settled slab. There seems to be an even more prominent resistance change between the mid pack slab and Facet/crust interface.
Skied low angle alpine terrain to access the TL/BLT for better ski quality. What's a little concerning to me is the steep wooded clearings Below tree line. There seems to be still a high concentration of sugar underlying the slab/storm snow. Poking around today in this type of terrain was a little alarming with the potential of triggering this type of terrain were lesser experienced ski tourers might think they are safe. Yes, these pockets might only go to size 1 or 1.5 but the real danger is the potential for severe trauma inflicted by the old growth. Something to think about as some operations are starting to trend BTL stability towards good!


Jon Simms
Asg

Since Jan. 1st I've dug 10 profiles in the Whistler/Blackcomb vicinity to examine the Dec. 6th FC/CR interface, all but one showing the same fracture character at each aspect and elevation. Most pits I tried an ECT with no results, the exception being a fracture line profile on 090101 giving ECTP(14) down 65cm on FC 2mm. I guess the taps aren't penetrating through to this layer in most cases with the ECT.

Elevations: 970 - 1950m
Aspects: SW, W, NW, N, NE, E
Dec. 6th CR thickness: Normally 2cm of knife, with P or 1F below
FC thickness: 12 - 24cm, up to 2.5mm grain size
Compression tests: CTE - H and one DTH, 6 x SC and 3 x SP (columns fell off and hit my legs). Only one pit in a deep snowpack area yielded no results.
1 x RB5 WB today
Fracture depth: 45 - 165cm (all within FC, normally a few cm from the top of the FC layer)
TG's: Now seem to be weak in all areas and the FC appear to be showing signs of rounding, though still feel very rotten in most areas.

The slab above the FC is stiffening, mostly P & 1F. Today when performing a CT, I dropped the column when picking it up to look at the bottom, and it didn't break.

All pits were either inbounds with no suspected skier traffic, or in the bc.

Alex Geary
ASG