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PostPosted: Mon Dec 21, 2009 6:37 pm
by seanpeckham
Went to Peak 10420 (near Clayton Peak) yesterday via its east ridge from the Guardsman's Pass road. Around the 10,000' level I dug a north-facing pit just off the ridge low enough to be sheltered but upslope from the forest cover. Found fairly strong pencil-hard depth hoar, but a crust sandwiched by weak facets above that. Got a full fracture propagation at the top of this layer (see 2nd photo), but only with hard pulling and levering with the shovel from behind, not with tapping or pounding on the top. Strong snowpack at this spot. But enough uncertainty as to how representative it was of entire slopes I was interested in, and severe enough consequences should you hit a thin spot in the overlying bridge/slab and initiate a fracture in those weak facets, that I stuck to lower angles. I'm still trying to get the hang of this decision process. The lesson is next time I need to find a pit location with a better chance of being representative of the weakest spots of a slope.
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PostPosted: Mon Dec 21, 2009 7:10 pm
by TyeDyeTwins
How do you post a picture on the thread? We want to add a picture to our observation yesturday and if anyone who knows how it would really help out.

PostPosted: Mon Dec 21, 2009 7:35 pm
by Ed F
How do you post a picture on the thread? We want to add a picture to our observation yesturday and if anyone who knows how it would really help out.


I just use the "Img" option at the top of the post (where the Bold, Italics, etc. are). You need to have the image online somewhere, such as here on SP.

I just set up an album for this thread here: http://www.summitpost.org/view_object.p ... _id=583973

It's public. Post your pics there and then just attach them to this thread using the "Img" option.

PostPosted: Mon Dec 21, 2009 8:07 pm
by TyeDyeTwins
AVALANCHE.... We went from Willow Fork (Wills Hill) to Beartrap yesturday. Went to ski the skiers left (the NW side) of Wills Hill. Knowing it was 30 degrees I had the avalung in my mouth as I dropped in. When I came to the roll over (just out of view of the ridge) the slope had already avalanched out. The crown was blown in (still 2 feet deep though) and our guess is that this one was a natural avalanche that occured early in the storm because the bed surface was actually good skiing. It was about 50 to 75 feet wide and I do not know how deep the deposite zone was (went to ski not avalanche hunt....sorry). Saw tons of large stress cracks and slides in North Willow on the way up to Beartrap Fork. We heard several whoomphs on the way down Beartrap. All day we observed huge surface hoar feathers on the shady aspects (2nd picture)
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PostPosted: Tue Dec 22, 2009 5:38 am
by PellucidWombat
For you backcountry snow travelers, here's a sample hazard map from a series that I'm thinking of making. Let me know what you think! Of course I know the map has scale limitations, but it seems like it could be a useful tool nonetheless . . .

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Avalanche Slope Hazard Map 1 - Alpine Ridge

PostPosted: Tue Dec 22, 2009 5:53 am
by Ammon Hatch
PellucidWombat wrote:For you backcountry snow travelers, here's a sample hazard map from a series that I'm thinking of making. Let me know what you think! Of course I know the map has scale limitations, but it seems like it could be a useful tool nonetheless . . .

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Avalanche Slope Hazard Map 1 - Alpine Ridge


I love it. From a climbers prospective, it looks like an excellent way to find safer routes for winter ascents, another useful tool for the bag. I'd like to see more.

PostPosted: Wed Dec 23, 2009 3:08 pm
by Ed F
For you backcountry snow travelers, here's a sample hazard map from a series that I'm thinking of making. Let me know what you think! Of course I know the map has scale limitations, but it seems like it could be a useful tool nonetheless . . .


Wow, neat stuff. What software are you using to create that? For touring, I use a Topo! map that I created that has ascent skintrack routes, skiing routes, sites of old avalanches, etc. on it, so I think all that plus your color code would make my map unreadable. However, I still think these maps are great for research and for a better visual interpretation of the slope angles. I'd love to see more.

PostPosted: Wed Dec 23, 2009 10:44 pm
by TyeDyeTwins
AVALANCHE..... Went up Noth Willow in Willow Fork (December 23) to ski North Willow. Every slide path along the ridge had extensive stress cracking and/or slides that broke to the ground. We skied one of the more conservative (30-33 degree) northly facing chutes in North Willow without incident. Went up to the Mule Hollow/Beartrap Fork ridge and heard one hell of a tree shaking, thunderous whoooomph on the notherly aspect. What suprized us is that there was an already well established skin track right there. Heard many more whoomphs on the way down Beartrap Fork and most of the steeper slopes had more signs of cracking. By the end of the day we were starting to get some surface sluffing on the steeper hills. The 1st picture attached is of one of the many avalanches we observed in North Willow (Willow Fork). The 2nd picture is of me skiing into North Willow with extensive stress cracks all over the chute.
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PostPosted: Thu Dec 24, 2009 9:04 pm
by PellucidWombat
sisyphus wrote:
For you backcountry snow travelers, here's a sample hazard map from a series that I'm thinking of making. Let me know what you think! Of course I know the map has scale limitations, but it seems like it could be a useful tool nonetheless . . .


Wow, neat stuff. What software are you using to create that? For touring, I use a Topo! map that I created that has ascent skintrack routes, skiing routes, sites of old avalanches, etc. on it, so I think all that plus your color code would make my map unreadable. However, I still think these maps are great for research and for a better visual interpretation of the slope angles. I'd love to see more.


It takes a while to make the maps, but once you have everything together, it's not too bad. I used a few sources to make this in a few steps:

1. Get free DEM files of the desired area from GIS Data Depot.

Files are organized by the geographic place name of the map, but it is easier to use the Lat/Long code and the ctrl-F browser search feature. It's a bit of a pain, but I've collected and merged DEMs for the entire Wasatch Range now.

2. Make map layers using any GIS software. I've been using MicroDEM which works well. In here I make 4 layers that are each saved as a jpeg for combining in the next step.

    A reflectance map to help bring out the 3-D shaded appearance of the final map.
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    A topo contours map.
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    A color-coded slope map, where I manually assign the slope increments (in %) to various colors.
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    A slope aspect map, which colors the map based on the direction each slope is facing. In this map I only used the N, NE, and E aspects.
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3. Combine the map layers in an image editing program with layers, such as Adobe Photoshop.

In this map, I did it in the following way:

    Base Layer: Reflectance Map - set at 50% opacity so that it doesn't make the rest of the image too dark.
    2nd Layer: Slope Map - using the "Multiply" layer option to allow the shading of the base layer to show through.
    3rd-4th Layers: Aspect Maps - I separated each aspect color into a separate layer by using the color selection option. In the separate layers you can then manipulate them further.

    In this case for the 3rd layer I represented N-E aspects (CCW) by selecting the shapes in those layers and filling them in black. The layer is set at 50% opacity. I also filled in the rest of the layer with white, which lightened the slope color map, making it easier on the eyes to read (the original colors are a bit harsh).

    For the 4th layer I only selected the NE aspect and filled it in black. For this map, 65% opacity seemed to be a good balance of bringing out the layer but not hiding the detail.
    Top Layer: Topo contours - using the "Multiply" layer option to allow the rest of the map to show through between the contour lines.


All done!

Then I just save the final map and bring it through Photoshop again for any map annotations that I want to add (in this case, the map key, route, camps, and feature names). So you could always selectively add a few of your map features to it (e.g. old avalanche sites), just taking care to not clutter it too much to be useful.

Since it takes a while to do this, but is fast once everything is set up, I wanted to make sure the current map style works well for people before I put too much time into making something that isn't yet optimal. If you-all think that the current map is fine, then in the next month or so I'll be making this sort of map for the Wasatch Range from the Wellsville Mtns down to Mt Nebo.

One change I think I will make is to eliminate the green color for 15-20 degree category. It is too hard to distinguish from the other greens, and my main color changes seem to follow general slope hazard categories: High = yellow-red-purple, medium = greens, low = blacks-blues. So I think I'll bump up the blues colors in the scale (so that 15-20 degrees is light blue) and make the 5-10 degree color gray to nicely transition between black and dark blue.

PostPosted: Fri Dec 25, 2009 9:25 am
by TyeDyeTwins
Went to Silver Fork in Big Cottonwood Canyon to Beartrap Fork. Saw several slides in Silver Fork. Over Easy (North Facing) had the largest crown and of interest we saw a deep slide that occured on a West Facing roll over (debries were 4 feet deep in an ugly terrain trap). All the slides we observed occured last week and seem to have now reloaded. We felt some collapsing (which is very different from a Whoooomph) in Silver Fork and in Beartrap Fork. While skinning up North Willow (in Willow Fork) we noticed considerable wind drifting on the north facing slopes. Surface sluffing was only an issue on slopes steeper than 35 degrees.
The 1st picture is of the slide on Over Easy.....
ImageThe 2nd picture is of the blown in crown on the roll over (west facing) avalanche

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The 3rd picture is of the debries from the roll over (west facing) avalanche.
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PostPosted: Fri Dec 25, 2009 2:34 pm
by Ed F
Haven't been out in the central Wasatch since last Sunday. Skied Summit Park area twice this week. It's still pretty shallow and difficult to ski. I have people in town until tomorrow, so hoping to get back out after that.

Just wanted to make sure people saw these:

http://utahavalanchecenter.org/snow_profile_willows_12242009
http://utahavalanchecenter.org/observation_willows_12242009
http://utahavalanchecenter.org/avalanche_dutch_draw_12232009

PostPosted: Sat Dec 26, 2009 3:39 am
by TyeDyeTwins
December 25th Observation..... Went up Mill D North in Big Cottonwood Canyon to ski Short Swing. When we reached the summit we saw an obvious sign that there are still instabilities in the northerly facing slopes. The slope fractured out in an area about the size of a living room but did not move very far. We were not sure if the area was a repeater or not because this was our first outing to this area this year. We skied the west facing trees without incident. The picture attatched is of the obvious sign of on going instabilities in the snowpack we observed at the top of Short Swing.
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PostPosted: Mon Dec 28, 2009 4:24 pm
by Ed F
Great new(?) website: http://www.wasatchsnowinfo.com/

PostPosted: Mon Dec 28, 2009 10:19 pm
by Ed F
Summit Park again--couldn't justify the drive around to LCC/BCC. Same old, same old. Still lots of cracks and collapses, although they are getting more difficult to create. All eyes to the next storm system headed through starting tomorrow. We really need some weight on this snowpack!

PostPosted: Tue Dec 29, 2009 4:32 am
by TyeDyeTwins
AVALANCHE........Did the Tri Canyon Tour today. When skiing Holy Toleto (west facing) we triggered a large sluff that covered up a few of our tracks. Many hours later we found ourselfs at the top of Little Water Peak. We checked the main bowl and found a recent avalanche just down ridge of the peak. We decided against skiing the main bowl due the recent activity in the area. The 1st picture is of our large sluff in Holy Toleto
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The second picture is of the avalanche just down ridge of Little Water Peak
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