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.
Bookmarks