2008-2009 Colorado Snowpack Observations

[Rontele]

looks like we may get something on Tuesday night/Wednesday....not much, a couple inches would be my guess. Friday could be something worthwhile, or it could be nothing. Hopefully it doesn't get cut off and we get a good storm. The 3rd thru the 15th or so, look to be sunny, dry, and above normal temps.

Is that according to accuweather? And this is always disappointing. Compare last night's five day QPF forecast:


with this morning's



Seems to suggest two things: 1) tomorrow night's system will be more progressive and shallower (the GFS, EC, and NAM all seem to agree upon this); and 2) the system for the weekend seems to dig further south and keep a lot of the energy at the base of the trough.

[lemon boy]

http://squall.sfsu.edu/crws/jetstream.html

The source link for the animated jetstream stuff, perhaps a little easier than the cdn avy thing.

[goldenboy]

Mtnbikerskierchick and I decided to explore around Greys and Torreys yesterday. There was a chute with some snow in it between the summit of torreys and the saddle. I made a ski cut in it, got a 5' x 5' x 1' chunk to come out. I was hoping that it was just near the ridge, so I went down a little more, hugging the rocks, but it stayed shitty- windslab on hoar. Took forever to sidestep back up and out all of 30' of vertical, but skiing down would have been really dumb. So basically, mbsc and I summited Torreys in AT boots with skis on our backs and then hiked back down, in the dark. We need snow.

the recent cold temps really started to make a crappy pack worse, as if that was possible. Things might get a lot worse before they get any better.

[montanaskier]

I was in Laramie, Wy over the holiday and while up in the Snowy Range I noticed surface hoar all over the place. Those crazy cold temps appeared to weak havoc. Be careful for sure.

[HikeforTurns]

Some whoompfing and cracking on NE ish cross loaded gullies around 12,000' near Janets Cabin on Saturday. Didnt have the splitboard, and didnt need it.

There was a line or two that was skiable, but sketchy, probably wouldnt get buried, but tumbling over rocks would be a significant hazard.

[pechelman]

saw cracking at the resort this past weekend as well on that same aspect
huge cracking too i might add.

[~mikey b]

from the CAIC forecast...

Weather Synopsis

We will see increasing clouds and strengthening winds today. They are coming in ahead of a low pressure trough that rapidly passes overnight. Conditions are favorable for snow--good dynamics, jet support--except for a lack of significant moisture in the air. A few flakes may fall in the afternoon, but the majority of the snow will fall overnight. Dusk to midnight brings the most intense snow to the Steamboat Zone, while the most intense snow in the Front Range, Vail Summit, and Aspen Zones will be midnight to dawn. Vail Pass, Gore, Park, and Flattop Ranges will do the best. The San Juans and Sangres miss out on snow, and only get strong ridgetop winds. With the snow comes wind. A jet core with speeds over 180 mph will move over northern Colorado. Ridgetop winds will be slower as the winds mix down, but expect gusts of 70 mph over the Divide and gusts over 50 mph elsewhere.

The storm clears quickly on Wednesday. Another quick disturbance brushes the Northern Mountains on Friday. This weekend looks interesting. The models have a closed low off Baja joining a trough. That throws a bunch of moisture into Colorado on strong southwesterly flow. Keep your fingers crossed.

I like this part.....

New snow from the incoming system will favor the Vail Pass area. This is a fast moving system, so expect it to be breezy. New snow and wind are like oil and water. Westerly winds over the past several days have been strong enough to transport snow onto north through east aspects creating isolated pockets of tender slabs above treeline. For the most part, these are the areas one would look for to ride. If you choose to ride, be prepared to test the snow stability on the slope in question before jumping in with a full commitment.

[Rontele]

Folks will have to be very careful on lee slopes. Forecast is calling for a 200kt jet core to be over the state tonight (telemike, that is the similarity between Nov. 1985). Its been 22 years since such a strong jet core has sagged over the state. Anyways, accumulations look to be in the 3-6 in. range with ample blowing snow. There is a whole lot of dynamics and orographics, but not a whole lot of moisture or duration with this sytem. My guess is that highlights should be issued with the afternoon package.

Looks like another, shallow wave for Thursday, with possibly a larger, moister system for this weekend (see the dramatic change in the five-day QPF fields above). Not surprising, the models have had a hard time building a consensus on the details.

[montanaskier]

This weekend does look like it "could" be promising. However, I am trying to not get my hopes up. Rontele, you still see a warm, dry period the first couple weeks of Dec.?

That is one ferocious jet....wow.

[Rontele]

This weekend does look like it "could" be promising. However, I am trying to not get my hopes up. Rontele, you still see a warm, dry period the first couple weeks of Dec.?

That is one ferocious jet....wow.

The jet is really, really, really impressive. Not sure about after Monday. Looks like a upper ridge will build back into the State. The long-range forecasts yesterday seemed to indicate, however, it would be pretty progressive. But given the fickle weather patterns this fall, I am not about to buy into anything quite yet.

[Hacksaw]

saw cracking at the resort this past weekend as well on that same aspect
huge cracking too i might add.

That is not very useful information unless you answer these questions.

When?
Where?
What aspect?
How big of cracking?
How was the crack triggered?

[pechelman]

^^^^

When? Saturday, could have been there before then though

Where? Keystone, visible from under the gonjola, prolly around 11k

What aspect? North to North east

How big of cracking? Anywhere from 10 to accross entire runs ~100ft

How was the crack triggered? I saw cracks propogating from things as large as sleds to as small as animal tracks that looked like foxes. The animal tracks leds to a small local slab failure where it fell into the old snow and shot out cracks ~10-15ft.

I had a hard time looking at all of them, because our cab had frosted over windows and was full of people, but suffice to say they were large enough for me to see.

The cracking however was fairly localized to a specific elevation.
My guess would be between 10,500 and 11,000ft.

hope that helps

[Hacksaw]

The cracking however was fairly localized to a specific elevation.
My guess would be between 10,500 and 11,000ft.

Pechelman,

All of that is VERY interesting.

But, the really interesting part is that the cracking was isolated to that elevation. Without getting to look at the snowpack up close it would be hard to say why the cracking was happening there. It could be a melt freeze crust, wind slab or even a fog/drizzle crust. Obviously, the colder temps made the surface a lot more brittle, thus the cracking. Very interesting that they ran soo long...

Thanks for the additional info. More info is always better....

[goldenboy]

Question for the weather geeks:

On the NOAA site, in the forecast discussion, they often talk about zone #x or zone #y. Is there a map that shows which zone is which, because I've never been able to find it.

[pechelman]

yea i really wanted to go poke around, and i didnt want my pass to get yanked, and i wasnt able to spot and stop a troller to talk to. If its still around this weekend Ill try again to talk to some of them, and hopefully get to dig around with them.

my knee wasnt really up to it either this weekend since i had bruised it a few days previous.

my guess, just looking at the terrain, as it was under a general rollover, that the cracking was a result of a windcrust, at least partially. as always there are so many factors that are involved. (ie just the terrain feature and possible windloading given prevailing winds)
I dont want to speculate beyond what I observed, but your temperature mention and brittle snow is accurate as well.

from the gonjola, id estimate the broken through potion of wind crust, where that animal fell into, was about 2-3" thick, or 50-75mm for you metric folk .

The same aspect and slopes so far this season have seen lots of surface hoar growth off to the east side of the trees where there has been some protection from wind, but just enough room for the surface to radiate off.

thats really all i got without digging around.

the thing that really caught my eye the most was the cracking that started from an animal.

[3DB]

Question for the weather geeks:

On the NOAA site, in the forecast discussion, they often talk about zone #x or zone #y. Is there a map that shows which zone is which, because I've never been able to find it.

Psychedelic Colorado:

http://www.crh.noaa.gov/bou/awebphp/zonemap.php

[Rontele]

Psychedelic Colorado:

http://www.crh.noaa.gov/bou/awebphp/zonemap.php

Good stuff!

[Hacksaw]

the thing that really caught my eye the most was the cracking that started from an animal.

That is scary..... Such a light weight trigger could cause such a long crack really does scare me.....

[smitchell333]

Loveland Pass today 11/27. Skied north facing 12,400 to below treeline. Where there are deep drifts (yeah - not that many places) the older snow pack is pretty firm and not showing much tension or weakness. Where it is and has been thinner its been rotted with some, although not super advanced, hoar.

On top of this where its been loaded and not blown off there is a tender slab of 6-18" that is prone to cracking and sliding if steep enough. I believe this is on the old crust alone, but could be some surface hoar.

Overall I think if we get substantial snow and winds the danger will shoot up as both the interface between old and new and where they'll be new drifts on thin rotted stuff may very well spell avy. Add on top of that that the pack is painfully thin, variability is high, and that the new snow will just cover rocks, stumps, ice and you have a recipe for caution.

[montanaskier]

looks like this one fell apart too. Less than an inch at my place, not snowing currentlly. SIGH

[montanaskier]

at 6:40AM....probably 2 inches at the house now. It is NOT windy where I am, however it is Never windy at my house. Was really hoping for at least 4 inches out of this one, however I will definately take what I can get. Fingers crossed for Saturday, but last night that didn't look good either. What say you Rontele?

[montanaskier]

and Rontele......Friday looks like reallly high snow levels for this time of year. 9k or higher, do you see that as well? Is it reallly going to rain on Friday?

[Rontele]

at 6:40AM....probably 2 inches at the house now. It is NOT windy where I am, however it is Never windy at my house. Was really hoping for at least 4 inches out of this one, however I will definately take what I can get. Fingers crossed for Saturday, but last night that didn't look good either. What say you Rontele?

4-6 inches at Vail Pass and still snowing. I would say it is pretty good.

The storm for Friday/Saturday is starting to phase together for the biggest event we have had thus far for this winter. Too bad, I am have a 40 mile mountain bike ride planned. Snow level looks to be at 8k.

[goldenboy]

Psychedelic Colorado:

http://www.crh.noaa.gov/bou/awebphp/zonemap.php

Thanks, exactly what I was looking for!!

[pechelman]

Too bad, I am have a 40 mile mountain bike ride planned. Snow level looks to be at 8k.

its never too late to go ski some pow


edit

I stand correct as this comes straight from the CAIC

The models still advertise a weekend storm. Plan a mountain bike ride or BBQ for the weekend, wash your car, do anything to encourage it to snow.