Avalanche Discussion

I'd like to spur periodic discussion regarding the accumulating snow pack in order to educate myself, and maybe others out there.

So far, it looks like there is going to be a 6-10" layer of ice in most places within the PNW. The storm activity to hit this weekend of 12/12-12/14 looks to bring Artic-air, cold temps, and a dumping of super light-weight dry snow.

Any thoughts on the future snow pack as influenced by such a sandwiched light-weight snow build on top of an ice layer??? Possible faceting, perhaps? Will this be a week layer to look out within the coming weeks of the season once we receive an additional 2-3' of snow?

It would be great to have a multiperspective dialogue going on snowpack.

I'll add what I put in a Paradise area report:

Things softened up just a tiny bit as we were leaving on Thursday (12/11). It doesn't look like the existing snow would've had a chance to soften up though due to continued cold temps and wind so most likely this current load is going to slide. Or maybe worse since this new snow has such a low water content it won't sufficiently weight the crust and the whole works will stay stable for a bit longer for more snow to accumulate on top, then once properly loaded it'll go.

Either way, we should see this crust layer on any pit that goes to within 2' of the bed surface with all this current fluff on top.

I'd love to hear others opinions as that's just my thoughts. I'm new to the whole telemetry thing so by all means if I'm way off base please chime in.

www.nwac.us/products/SABSEA

Emphasis added ...

BACKCOUNTRY AVALANCHE FORECAST FOR THE OLYMPICS WASHINGTON
CASCADES AND MT HOOD AREA
NORTHWEST WEATHER AND AVALANCHE CENTER SEATTLE WASHINGTON
0830 AM PDT SAT DEC 13 2008

[...]
SATURDAY NIGHT THROUGH SUNDAY NIGHT
Strong east to northeast winds are expected in most
locations late Saturday and Sunday along with bitterly
cold temperatures. While decreasing light showers are
likely in the north with gradually decreasing light to
moderate snow or snow showers in the south, the
increasing and shifting winds combined with very cold
temperatures should still help to produce a further
slight increase in the danger. The danger increase should
be greatest on west to southwest exposure slopes above 5
to 6000 feet where locally considerable danger is
possible on steeper terrain with a smooth underlying
ground surface or on slopes where most anchors have been
buried. Travelers are urged to perform stability tests
before traversing steeper wind loaded terrain, especially
in higher elevation wind loaded terrain, as the cold air
temperatures and associated strong temperature contrasts
in the snowpack should help weaken the bond of recent
snow to the pre-existing snow surface.

A significant danger may also exist from the expected
weather in most areas. The combination of very low air
temperatures and strong winds should produce wind chills
dropping to well below zero. Back country and other
travelers are urged to take precaution to protect exposed
flesh and minimize time exposed to the wind. While some
partial clearing is likely, especially in the north later
Sunday, blowing and drifting of the very low density and
fluffy surface snow should produce reduced visibility and
difficult travel in many areas.

Please also note that the cold air temperatures combined
with the still relatively shallow snowpack should result
in significant faceting and weakening of the overall snow
structure later this weekend and well into next week.
This greatly weakened structure will become a substantial
avalanche concern whenever future more normal and
generally warmer conditions deposit higher density
snowfall over the generally weak and still relatively
shallow Northwest snowpack. The anticipated development
of some surface hoar in wind sheltered areas when skies
begin clearing late Sunday into early next week will only
add to the potential for a rapid avalanche danger
increase when the next significant snowfalls arrive.

How about going to dig a pit on top of Goat Island Mountain? That would be an enjoyable slog.

It would be great to have a multiperspective dialogue going on snowpack.

I'll add what I put in a Paradise area report:

Things softened up just a tiny bit as we were leaving on Thursday (12/11). It doesn't look like the existing snow would've had a chance to soften up though due to continued cold temps and wind so most likely this current load is going to slide.  Or maybe worse since this new snow has such a low water content it won't sufficiently weight the crust and the whole works will stay stable for a bit longer for more snow to accumulate on top, then once properly loaded it'll go.

Either way, we should see this crust layer on any pit that goes to within 2' of the bed surface with all this current fluff on top.

I'd love to hear others opinions as that's just my thoughts. I'm new to the whole telemetry thing so by all means if I'm way off base please chime in.

Great! Thanks for the perspective analysis. That's exactly what I'd like to evoke...

And thanks Lowell for the info.

Tell your partners about this thread and let's keep a continuous dialogue going and keep it on topic throughout the season.