Building the Colorado snowpack

[FrankZappa]

the mid pack layers were once the near surface facets or possibly surface hoar. they grow the same as the depth hoar you see at the bottom but in the opposite direction. the crystal builds layer upon layer in what resembles a trapazoid. the widest end is the most recent and the direction of the vapor transfere.

frank, if you'll look back through the avalanche review of about 2 yrs ago, there's a really good article on vapor trasnsfere and faceting around crust layers/impedence layers (above and below).

Thanks APD. Makes good sense.
Why do they always seem to be below hard layers? (see post above from CAIC)

Got a link for Av Review?

[Ermine]

Got a link for Av Review?

A few here:
http://www.americanavalancheassociat...lications.html

I never remember the site, just go to avalanche.org and AAA

[FrankZappa]

Well, we talked about gettin' some rain to come in and wash away that snow we had so we could start over. Seems like we've been getting that with this warm southerly moist flow for almost a week now - at least west of the divide.

Sounds like the San Juans at least have been hit with a deluge and temps from the Red Mtn. recorder were staying above freezing up 'til yesterday.

It's finally raining a significant amount here in the upper Ark. (south Sawatch) and what was left of the mid Sept storm was getting very thin. Only dustings above 13k twice in the last week. Today, cloud ceiling at about 9,000 with no sign of snow yet.

Whats the word? Anybody been up there to check?

How's this relate to the earlier post about the ideal lead into the season with cool rainy weather?
Is it enough rain (too much)? What's it doing say above & below timberline? Implications?
If it's wet & heavy up high where the previous snow is holding, What's that gonna do to the pack?

Inquiring minds want to know...

[goldenboy]

It's finally raining a significant amount here in the upper Ark. (south wasatch) and what was left of the mid Sept storm was getting very thin.
Whats the word? Anybody been up there to check?

Sick! I'll be moving to your neck of the woods now that the wasatch is there Word is that snowline is moving lower now. I'll be going over cottonwood or monarch tomorrow and let you know.

[FrankZappa]

Todays history lesson:
Geoligists and bioligists believe they have proof that billions and billions of years ago the Sawas mountains were one in the same. Giving birth to the ancient one (Sasquatch and his evil and worthless twin Saguache) and raising them until they were old enough to be on thier own. One went to college in the PNW. The other just hangs out in the Valley being molested by visitors from outer space.

The Sawas no longer got along, so they parted and went thier seperate ways.

The mighty Sawatch stayed near his many friends and relatives where he was tall and above almost all others.

The Wasatch became a Morman, and we all know where that trail ends.

Over the many long seasons of the wind and water and ice, some tounge tied idiots still refer to one or the other Sawas as one or the other, or some deranged derivative, as in the "Sawasawhatchamicallems."



You know what I meant, wise guy.

I'll be off editing my post now.

[FrankZappa]

Just so theres some record of this stuff here.
River flows or the past southerly storm cycle in the San Juans.
and some weather station readings reflecting the still "warm" temps at 3 sites. Red Mtn pass - Eagle, McClure pass between Delta & Carbondale, and Wolf Creek.

Attachment 16650
Attachment 16651
Attachment 16652
Attachment 16653
Attachment 16654

Note the weather sta readings show only the last 24 hours or so which have been a few degrees cooler than the previous days.

[lemon boy]

Sat- Mixed rain/sun all day in N. Park mild temps even up high still (iskibc- parkviews not really holding as of Sat)

came back from SLV yesterday - pissing rain up to ~10K higher obscured, changed to snain across S. Park so I'd expect a fair amount of snow up high. I did get to see a quite spectacular moonrise over the sagres Sat night.

[FrankZappa]

Did you run into the evil and worthless twin Saguache down in the Valley?

Poncha Springs area this AM: 40° f at 7am. Light rain all night. Ceiling at 9k at first light dropping to below 8k by 7:30.

Using the rule of thumb that one could expect a 4° f temp drop per 1,000 ft elevation gain, and it being 40° at my 8,000 ele, I predicted the snow level to be at around 10k near the Monarch dist.

With continued moisture and another cold front expected w/n the next few days, we could start a decent build again, and maybe it'll stick around this time.

More for the record. - It's sticking to the pavement on the south end of the state. But Vail pass still looks clear. Temps look good on Red Mtn but boarder line at WC.

Attachment 16661

Attachment 16662

Attachment 16663

Attachment 16664

Attachment 16665

[lemon boy]

Did you run into the evil and worthless twin Saguache down in the Valley?

uuuuuhhhh....huh?

but I did go through saguache and camped right near there.

[FrankZappa]

uuuuuhhhh....huh?

Refer to post #80 for therory of Sasquatch and his evil and worthless twin Saguache.



Bird huntin'?

[lemon boy]

duhhhhhh sorry. I sorta skimmed that part. I would say that I did have a "close encounter" with one as when I pulled into my "campsite*" I smelled a very odd rotten meat & sage smell** (I imagine this is what Scott Gaffney's house smells like right now....BURN!).

Yes, duckin all weekend, it pissed rain all Sun morning on us, chest waders are superior rainpants.


*place I parked the truck for a few hours
**true, not overpowering enough to make my want to move though

[goldenboy]

Around noon, snow was not sticking to the road at monarch, maybe 3 or 4 inches tops on the grass at the pass level. Snowline looks to be more like 11k in CB. There has to be a lot of snow above treeline after the last week of warm moisture (cue another sweet montezuma TR now....)

[FrankZappa]

There's a lot going on out there. I hope it'll keep up. Just need the temps to drop a lil' more to turn the rain to snow, which they finally are doing (snow down to 7k here this am), keep getting consistant storms (in the form of flakes, please) and in a couple weeks we might be on our way to a good season.

First for the "very" high country, refer to TR: Fourteeners and Faceshots 10.9.06 update from iskibc, Funkendrenchman, Figure Eleven, Dside 11. I think these guys were up around north central CO.

A nicely consolidated 4’ base covered the ground. A good 6” of light and airy snow had fallen the night before. The higher and higher we climbed up the couloir, the snow got deeper and deeper.

This sounds really good to me.
Any thoughts on this "consolidation" factor? - warm moist system and it's bonding properties...?


Then near timberline (10k-11k) in central CO: listening to my pager for a cattle truck off the side near the summit of Monarch at 9pm last nite and the associated radio traffic talk of blizzard conditions, 50 yard visablity, along with semi trucks not being able to set thier brakes (the rigs just slipped away w/ the wheels locked under the weight of the vehicle).
I think lots of the previous snow at and below T-line had been melted away (around here at least). So for the most part it's starting over on the build. And the ground surely is colder now than it was after having that snow from the other week on it and then some rain.


An E-mail from a friend in Silverton over the weekend stating that Mineral creek above town was jumping it's banks on Sat. His thoughts on that area:

All this rain is supposed to turn to snow up high this evening so we'll see what falls out by the end of the week. If it's snow it'll be on a base from two weeks ago. Time to start digging pits and tracking it.

and the lower country report from storm11 Late Season STOKE! - UPDATE W/ PICS about HUGE river flows. - larger than spring runoff.

Over the past 3 days the Animas went from 300cfs to 7900cfs

[FrankZappa]

... and Monarch is still holding in mid afternoon Even though it's been sunny down here in town since AM.

------------------------------
Monarch Pass

Air Temp: 28°F, 0°C
Air Pressure: 65535
Dew Point: 27F
Relative Humidity: 96%
Wind Speed: 11 mph, 10.0 knots
Wind Direction: N or 20.0°
Wind Gust Speed: 16 mph, 14.0 knots
Wind Gust Direction: N or 358.0°
Precipitate: 1
Precipitate Type:
Precipitate Intensity:
Precipitate Accumulation:
Visibility:
Reading taken at Tue Oct 10 13:40:00 MDT 2006

[iskibc]

First for the "very" high country, refer to TR: Fourteeners and Faceshots 10.9.06 update from iskibc, Funkendrenchman, Figure Eleven, Dside 11. I think these guys were up around north central CO.

This sounds really good to me.
Any thoughts on this "consolidation" factor? - warm moist system and it's bonding properties...?

.

The 4' base I was talking about is mostly the terrain above 12.5K in the Montezuma basin area. Pearl Pass looked to be holding around 1' or so of snow. The north couloir off Castle had a good 3.5-4' base. Conundrum was deeper, but definitely wind effected. Both situations the pack was looking good. No distinct weak layers were present, except for maybe the wind slab that was beginning to form on the upper parts of Castle Peak and Conundrum. It appears that snow has been slowly accumulating up in that area on a fairly consistent basis, which is good. No signs of dh or tg upon inspection.

Right now there are a wide range of conditions in Colorado. There are a wide range in base depths as well. For instance, most of the Castle Creek area had about a foot of snow on the ground above 11K. Driving home and checking out the Mosquitos and Tenmile, it was very patchy, with some peaks holding no snow whatsoever, and the nextdoor neighbor peak holding a good foot or so. Lot's of peaks and starting zones from Leadville to Frisco have a light dusting (depth hoar written all over it) that looked to have been from a few days ago. Very spotty too. I think this goes to show how spatial variability and trigger points will play a role down the line. Lot's of landmines forming out there right now.

[smitchell333]

Dave,

Was the 4' base all new snow or was there some snow left from last year in the basin and chutes?

Finding and getting to the spots with enough snow to ski is a key challenge right now.

[iskibc]

Dave,

Was the 4' base all new snow or was there some snow left from last year in the basin and chutes?

Finding and getting to the spots with enough snow to ski is a key challenge right now.

Conundrum was holding some old snow from last year near the top of the chute. Down lower it was all new snow. Castle was all new snow. A good 3' or so in the chute and on the apron. 'Zuma obviously has old snow underneath, but I was able to dig down a good 90-100 cm through the new snow before reaching the old hardened snow. Elevation obviously is key, as once we got down 750' or so, there was only about 12"-15" of snow on the ground.

[smitchell333]

Nicely played - when I saw FigureEleven's report last week I figured that was the spot to be.

[iskibc]

Nicely played - when I saw FigureEleven's report last week I figured that was the spot to be.

Yeah, worth the drive for sure. However, after this last storm I doubt you will be able to drive up past treeline any longer. It was sketchy enough yesterday to get up to one of the last switchbacks. Will be a fairly long haul from below treeline.


On another note, I'm really amazed at how new snow bonds so well to old 'glacial' snow. I always thought glacial snow would be a great bed surface for something to run on. It must have something to do with it's surface area and the texture of the old snow.

[FrankZappa]

On another note, I'm really amazed at how new snow bonds so well to old 'glacial' snow. I always thought glacial snow would be a great bed surface for something to run on. It must have something to do with it's surface area and the texture of the old snow.

Do you tink it had anything to do with possibly pre-rain on the old changing to snow?
or maybe just heavy wet snow on it?

[iskibc]

Do you tink it had anything to do with possibly pre-rain on the old changing to snow?
or maybe just heavy wet snow on it?

Possibly. I also think that when new snow falls on old 'glacial' snow there's some quick melting>freezing>melting>freezing sort of cycle going on which bonds the two surfaces together quite well. I don't know, just speculating.

[FrankZappa]

It kind of makes sense to me if the two were wet/damp, say in the afternoon, and the temps droped there might be some freezing together/fusion type thing as the new snow would go from wet to drier - before it got too deep to insulate the mating surface.

I'm speculating too, in case you haven't noticed.

[smitchell333]

It kind of makes sense to me if the two were wet/damp, say in the afternoon, and the temps droped there might be some freezing together/fusion type thing as the new snow would go from wet to drier - before it got too deep to insulate the mating surface.

I'm speculating too, in case you haven't noticed.

Of course assuming that the old stuff is basically ice or close to it we can expect TG to be created at that old snow/new snow interface and resulting hoar development as long as the snowpack above is shallow enough.

[goldenboy]

maybe I'm just old and senile, but I can't remember such a difference in snowpack levels based on altitude. Right now, there is basically no snow here at 9500', some friends of mine went to Baldy 3 days ago and found only a foot at the 12,800' level (and Baldy tends to get a lot of snow), while at 14,000' on Castle there is 3-4'. Baldy is only about 10 airmiles or so from Castle. We would have had so much snow in the last week and a half, but most of that moisture was rain, except at the highest altitudes.

[smitchell333]

Sure signs of the TG/Depth Hoar from the sound of it. Where it isnt deep (less than 20" maybe??) and/or ski pressured I would imagine much of what's up there is substantially faceted. Going to be interesting...

FigureEleven checking out our intended line:




Underneath the wind slabs we found some faceted snow about 12" deep on top of rock. Not looking good at all. This was the point where the weather went from overcast to downright white room where you couldn't see 15' down the slope. All in the matter of a couple of minutes. The decision to bail on this line came quick and we decided to head over to the north couloir and give that line a try...

...In just the past few days the stability and overall strength of the snow pack has diminished considerable. I'm starting to see a much more winter-like snow pack in that the winds have created pockets and areas of instability and danger within the snow pack. Be careful out there and have fun.