Snow Stability Assessment and ski/riding conditions for Pilot, Freeman, Sunset Peaks, and other Backcountry destinations in Central Idaho and Eastern Oregon.
Tuesday, January 22, 2008
Mores Mountain: 1.21.2008
A snowpit PLUS was done at the location on the topo map corresponding for the M of "Mtn". The snow pit chart is included below. I was quite surprised by the shallow snowpack at Mores compared to the much deeper snowpack everywhere else in the Boise mountains.
Even when this BLOG is meant for Mores Creek Creek Summit, many of the same backcountry recreationists that frequent Mores Creek Summit area also spend time around Mores mountain. In addition, considering how shallow, punchy, and facetty the snowpack is at Mores mountain - it makes sense to make the backcountry community aware of the conditions.
I suspect that the two strong winds events of the last weeks transported much of the snow from the East Faces immediately below the Mores Mountain Summit farther into the two Chutes/Gullies to the north. These two East aspect chutes appear to have better snow coverage.
Under the new snow there is a wind crust layer, but as I approached the descent line (in red in topo map) there were places were the ski penetration went from 10 cm to considerably deeper into the snowpack (30 cm). These are weak spots, where the weak layer at 25 cm could be easily disrupted. However, after descending a couple hundred feet - the crust becomes supportive.
I recommend to carefully evaluate More Mountain steep East chutes during the next weeks. A loading event or thaw could provide conditions for snowpack instability.
Stability tests suggest "FAIR" stability due to moderate snowpack strenght (CTM), moderate fracture initiation energies (Q2), but poor fracture propagation (ECTN). However, considering the HIGH variability and poor structure of the snowpack [weak layer buried in the top meter, persistent grains - facets, concern layers with more than one step in hardness, and weak layer thinner than 10 cm] it is likely that there are sweet spots capable of producing localized slides.
It should be noted that other "out of bounds" terrain we skied yesterday with north exposures (6400-5800 feet) on the ridge accesible through the resort "Stump Patch" gate were also shallow, and mostly composed of facets below the top 30 cm of recent snow. But there was suffient snow covarage to allow for FANTASTIC turning in those Northerly shots.
And PLEASE, PLEASE, PLEASE - we need you to BLOG too - and share with us your valuable observations.
Saturday, January 19, 2008
Mores Creek Summit Snotel Data: 1.19.2008
Getting back to business, the Mores Creek SNOTEL data suggest that the snowpack has settle by as much as 12-13 inches since the last storm cycle. This settling is benefitial, since it generally leads to a more stable snowpack by reducing the shear stress caused by differential creep rates.
The SNOTEL summary data for the season is included below:
The temperature data suggest that a melt-freeze layer and/or sun crusts might have developed after 1/12/2008 at some elevations and aspects, and that there was a significant cooling period (1/16-1/17), quite possibly resulting in the formation of surface hoar or near surface facetted crystals. However, the wind might have obliterated or inhibited the formation of surface hoar.
Can we get snow conditions observations posted on this blog? That is the purpose of this Blog.
In a different note, we need to be good stewards of the Mores Creek Summit area and follow some simple "ettiquete" and safety practices:
- Please step-off the the trail when in need of watering the lillies. Yellow snow on the trail is very unsightly.
- Remove the dog curd from the trail. It is even worse than yellow snow. We do not want to end up like in the Wasatch, were dogs are banned from the winter backcountry trails.
- Be mindfull of the up-hill trail routing, plase attempt to avoid having a trail that will result in riders skiing above YOU.
- Also, be mindfull of parties at the bottom of a slope - do not ski/ride above them.
While skiing at Teton pass this week every one of the above rules were disregarded. Mores Creek is nowdays a very popular backcountry recreation location, and follwowing the above rules will make the experience a better one for everybody, and SAFER too!That's all I have for now. I will blog again, once I can get to the Mores area within the next few days. And again, we need your observation ... do not be SHY!
Sunday, January 13, 2008
Pilot Peak Report: Saturday January 12, 2008
Thursday crust could be easily felt with a probe or during trail breaking - but it did not affect downhill riding at all. Reports from friends that skied Pilot and Freeman were very disconcerting; bruised knees (ouch!) during tele turning, and in Mike's words - "plates were flying up as we bashed through it skiing downhill".
Considering the strong wind events and good amounts of snow deposited during the week, in addition to changes in temperature during the storm, higher density snow in top of lighter cooler snow and variable snowpack, it made sense to perform several "SnowPit +" (it sounds better than hasty pit) at various locations during the day.
Three test pits were done at Pilot Peak with the following results:
- East aspect at 6900 feet, 30 degree incline- CTMQ2 (with sudden collapse) and CTMQ3 at 50 cm on a 4-5 mm weak layer of stellars and light precipitation snow crystals. Canadian extended column (undercutting WL with saw blunt side) did not propagate fracture.
- NEE aspect at 7200 feet, 32 degree incline - CTMQ3 at 50 cm
- NE Aspect at 7000 feet, 30 degree incline - CTMQ3 at 50 cm
The new snow in top of the crust did not show clean planar shears in our test, perhaps due low cohesiveness and bonding of crystals resulting from the relatively warm temperatures.
None of the pit sites appeared to be affected by windloading. We only examined the top meter of the snowpack, but each of the pit profiles were pleasently consistent on the layering thickness and structure. The top meter snow profile for site 1 is included below:
A quick view into the structure suggest the following "Lemons" (or elements present in most historical slab avalanches):
- Weak Layer within the top meter.
- Weak Layer thickness less than 10 cm.
- Hardness difference across Weak Layer of one step. Notice that the pit data documented a hardness from F+ to 4F, hence it can be argued that the hardness difference is less than one step. But considering the subjective nature of hardness estimation, it is prudent to treat it as a full step.
No persistent grain type or differences larger than 1 mm in snow grain size were detected in the top meter of the pack. Also, it should be noted that as the day progressed the compression tests were showing more irregular and "broken-up" shear planes. A suggestion of weak layer metamorphism at the 50 cm depth.
So, how do we make sense of all of this information? There are four categories that should be consider during a snow stability assestment; snowpack strength, fracture initiation, fracture propagation, and snowpack structure.
- The snowpack strength is Moderate based on the CTM results. Keep in mind that snowpack strength is sensitive to spatial variation. Rock bands or weak spots (for example snowpack thining due to wind) will have an impact on the strenght and stability tests such as compresion tests.
- Fracture initiation is Low based on the Q3 results. Studies suggest that this parameter has less sensitivity to spatial effects.
- The Extended Column test and observations of the pack during trail breaking points to Low Energy available for Fracture propagation.
- A review of the snowpack structure results in 3 Lemons.
The good news is that the slopes evaluated did not appear to have energy available for fracture initiation and propagation. The NOT so good news is that the strength is moderate and there are 3 Lemons. We acted on this information by not skiing slopes that reduced strength or exacerbated the effects of structural weaknesses. This was easy since the area we skied lacks slopes steeper than 32 degrees, there are no rock bands, and no obvious wind loading effects/features.
Temperatures during the day fluctuated between 28-30 deg-F. It was nice that the predicted hi of 34 deg-F never materialized due to overcast and obscured skies later in the day. Did you noticed the formation of a very thin layer of surface hoar in open slopes with N and NE aspects above the 6500 feet level? We need to keep an eye on that layer.We had a fantastic day of skiing, but my 14 year old "knuckle dragger split boarder" son was almost KILLED by a falling diseased/dead tree. Suddenly without any warning a two feet diameter tree started to squeak and came down - he had the presence of mind to step back several feet saving his own life! He was VERY glad about not bringing his Ipod.
Some of you that used the track I put in at Pilot's North side will have notice that this BIG tree was blocking the trail at the 6600 feet elevation. The wind was light at the ridgetop, and calm everywhere else in the hill - the trees are just overloaded with snow. PLEASE - BE CAREFUL! I do not know about you, but from now on I will keep my uphill track away from sick-dead trees overloaded with snow.
I have to say that although Mores Creek Summit area has surely changed - there were lots of NEW faces yesterday - I am VERY glad that MANY will enjoy the beauty of this area - and collectively treasure this Idaho gem.
Hey Carl and Irene - I was glad to see you yesterday. It has been a couple of years since I have seen you. Hope to see you more often in the backcountry.
Finally - WE NEED MANY OF YOU to step in and contribute to this blog. I will be gone for a week (Jackson Hole), thus I will not be able to provide updates for a week.
Pray for more snow - especially cold smoke!
Thursday, January 10, 2008
The Mores Creek Summit is a popular winter recreation area with fabulous terrain and incredibly varied winter touring opportunities. It is indeed a precious gem. I had been skiing there for 15 years, and it is where my kids developed their backcountry skills while skiing at Freeman and Pilot Peaks. For this reason this area very special to me.
During the last few years the winter visitors to Mores Creek Summit has dramatically increase. Information about snow conditions was shared by word of mouth. But that is not adequate anymore, and it is my hope that this blog could serve as a tool to better share snow conditions, as well as allow for the local backcountry community to network, share snow stability assestments, and make friends.
I think it will be a good idea to start this blog by inquiring about potential names for the most popular ski runs. In the spirit of initiating the conversation I include below a topo map with names used by my sons, acquaintances and myself. I have NO idea how we will reach concensus - but we will figure it out together as we go forward.
The next posting (this weekend) will have the first snow assestment to be posted on this blog. Snow assestment for the early season is available - but the NEW snow from the 1/7 thru 1/11 - makes the pre-1/7 data less valuable. Let me know if there is interest on it and I will be more than happy to post it.
One final note: In order improve communications it is strongly suggested that we follow the guidelines and conventions from Snow, Weather, and Avalanches: Observational Guidelines for Avalanche Programs in the Unites States.
I recommend purchasing the document at: http://www.americanavalancheassociation.org/obs.html
or printing it from the following link:
Furthermore, I will be sharing snow assestmant data based on the Snow Pit Technologies " Snow and Avalanche Field Book", also known as the BLUE book. The field notebook can be acquire at: