Saturday, December 30, 2017

The Knob (Pilot Peak) - Little new snow, a new rain crust layer, and Good Skiing!

As we drove past Idaho City this morning it was raining. We became somewhat concerned. As we gained elevation rain continued. It finally transitioned into snow past the Freeman switchback (Mores Creek drainage), just 100 feet from Mores Creek Summit.

It was somewhat disappointing to realize that the Thursday and Friday night storms forecasted snow amounts, storm totaling 20 cms of snow precipitation,  did not materialize. Above 7000 feet and at locations minimally impacted by the moderate winds, there were as much as 3 cms of new snow. In other more windward locations, the sheer glare of the rain crust was very visible.
At all elevations and aspects, under a thin layer of Friday morning snow, a thin rain crust layer was present. At elevations below 6500 feet, the crust became started to impact the quality skiing.

During the last two visits, the snowpits were located 10 meters below ridge tops. Today's snowpit was located 100 meters from the top. The structure was similar and the only remarkable difference was that the weak layer was only 3 cm thick, quite thinner from the 9-10 cms thickens at below the ridge tops at Summit Creek Glades and Almost Top of the World.
The pit profile is included next;
Stability test results are similar to the December 25 and December 27 stability tests. The next video shows the compression, extended column, and cross-propagation saw, and regular propagation saw tests.

KnobDec30_2017 from Santiago Rodriguez on Vimeo.

In the video, you will notice that we continue to play with the experimental horizontal PST, also called "cross" PST or CPST. Today stability test results continue to be consistent with the stability tests conducted during December 25 and 27th. In addition, the PST for the three days (December 25, 27, 30) arrest the fracture propagation after the slab fractures. I am uncertain of why this was observed again today. The warm temps and rain have greatly increased the strength of the slab. Reviewing the pit picture of snowpit reveals that the slab hardness goes from Fist at the top to 4-F at its bottom.

I did not observe surface cracks today, but ominous whumpfs were still frequent. These whumpfs are consistent with the stability test results. Based on this test results we avoided slopes above 35 degrees and used an inclinometer to verify slope angles.

The skiing was surprisingly fun. When skiing, as we lost elevation elevations the crust transitioned into a thicker crust. This crust, depending on aspect, had the potential of increasing the instructional level of skiing. But we selected ski lines with NNE aspects as well as protection from the wind. We suspect that the protection from the wind minimized the amount of liquid water reaching the snow surface from a light rain event last night.

The sky partially cleared late in the morning and we were rewarded by wonderful views of the Boise, Sawtooths, and Trinity Mountains.  Check the next sequence of photos. Can you recognize Copper Mountain at Banner Summit?

Friends continue to ask me about coverage. If you use Pilot Peak road, you can skin to above 7000 feet to reach the Upper Summit Creek Glades, The knob, Almost Top of the World, and Top of the World. The coverage of the North and East aspects is adequate. You just need NOT get carried away and drop into the Summit Creek drainage below 6400 feet.

Check the next two pictures. The top picture was snapped from the Knob, looking north into "Top of The World", and the second picture is looking south into the upper Summit Glades. These pictures should give you an idea of the coverage above the 7000 feet level.

Yes ... it is not ideal the shallow snowpack we are skiing at MCS. We are 50% off from the average depth for this time of year.

Yes, we need to be conservative with the fracture propagation propensity of the snowpack. Persistent slabs are unpredictable.

Yes, we need to carefully select ski lines to avoid deadfall that can hurt us. Use existing Forest Service roads to get to higher elevations and avoid skiing shallow areas below 6500 feet, where your skis can get snagged.

But it is not a bad idea to go out and train your body for the skinning required by the powder days coming soon. Besides, it is a great idea for those that have taken avalanche courses to practice stability tests and experience first-hand how an unstable snowpack behaves during testing.

Happy New Year!

Friday, December 29, 2017

Ski Tour Planning for MCS - What resources should I use before skiing tomorrow?

Today I was pleased to see the use of the term 'Situational Awareness" in a Facebook posting by the US National Weather Service-Boise. There has been a lot of conversations during the last few years about decision making in Avalanche terrain, as well as the importance of trip planning. However, we have been slow integrating situational awareness (SA) into decision making. SA has been important to big wave surfers as well as sailors. I grew up doing both. In order to survive and enjoy the power of waves and the ocean (in a surfboard or sailboat), we where disciplined (maybe obsessed!) about perceiving, understanding, and anticipating nature.

So how do we use SA for planning a ski tour at Mores Creek Summit? First, let's examine the perception of the environment. The avalanche environment is the combination of snowpack, weather, and terrain, as well as our touring companions when in the mountains. We will discuss each one.

Check the forecasts for the Payette Avalanche Center and/or Sawtooth Avalanche Centers. If you have been doing that for a week or so, you might have noticed a discussion about the development of a "persistent slab" avalanche problem this winter in Central Idaho.

How a persitent lab is formed? As the precipitation snow sinters and settles (densifies), the slabs progressively becomes more cohesive. Wind or terrain with shallower angle intensifies the slab formation. The Christmas snow has now become a slab and it buried an old snow surface. The old snow surface was transformed into facets during clear weather. The facets become a weak layer once buried by a slab. This weak layer consists of persistent crystals. They are persistent because it takes a long time compared to new snow to round and form bonds (sinter) within its crystals.

Facet crystals due to their highly hexagonal crystalline structure and lower surface area per volume take longer to transition into rounds and sinter. By recalling the Southern Idaho weather trend (tranquil and dry with snow in the ground) and the latest new snow that had enough time to develop a slab, we should suspect that we might have a "persistent slab" problem type. And that is confirmed by the Avalanche Forecast Centers in their latest forecast products. In addition, there is data from friends and others (like this blog) that have documented the presence of persistent slabs in some areas.

We have identified one of the avalanche problems "type" of the day, a Persistent Slab Problem. Check this resource to become familiar with the various avalanche problems:

If we intend to ski at Mores Creek Summit tomorrow, the avalanche problem type defines the snowpack we will be traveling and skiing on. We discussed meteorological factors that resulted in the Persistent Slab problem type present today at MCS. But we also need to consider how the weather conditions will impact the snowpack now and during the hours prior to our tour. There are two elements for the weather "environment"; what is going on right now, and what will happen tomorrow.

For present conditions, I suggest where you can select all weather stations within a certain area or radius. The interface looks like this when you also select the radar layer:
If you zoom into MCS area you get two stations; one at the top of Pilot Peak and another at the MCS snotel.
Clicking on the stations (for this case Pilot Peak Summit) a graph pops up with Temperature and Relative Humidity. You can also select wind and solar output charts.

The chart is important because it shows that temps at the top of Pilot Peak have been between -3 and -1 Deg C during the last 24 hours. These temps would have resulted in further development and strengthening of the persistent slab at MCS.

From the same Mesowest menu you can access the wind data:
The wind speed is increasing as the storm approaches. The wind direction at the top of Pilot Peak is from the SWW. The wind speeds are moderate, and two days ago there was snow available for wind transport, thus it is possible that localized wind slabs might form near the top of Pilot Peak. This is a second avalanche problem type so far identified.

If you click on the Snotel station you get temps above the freezing point for the last 24 hours. Thus it is possible that a crust might have developed at the snow surface prior to the new snow precipitation event. Or perhaps, there will be an interface between precipitation events. Can this result in a shallow storm slab problem between the Thursday and Friday precipitation events?
The Snotel stations are managed by the Natural Resources Conservation Service. An interactive map can be accessed at Depending on what parameters you choose it might look like the shown below. I like to display the snow depth variable.

Move the cursor over the Snotel stations and select MCS station. By clicking on the station you can get into a 30-day or 7-day report. Or you can create a custom report, just like the one shared below.
You can scroll the mouse pointer into the precipitation data points. For the above chart, there was an increase in snow depth from 61 to 71 cm. In summary, during Thursday night, 10 cms of new snow precipitated at 6100 feet (elevation of MCS Snotel). Temps at 6100 feet have been above the freezing level favoring slab densification and a possible development of a crust, factors to consider when another precipitation event will deposit additonal snow. On the other hand, Temps at Pilot Peak summit have been below the freezing point and in combination the SW wind it is reasonable to expect the formation of wind-slabs as well as the transport of snow in some areas (cornice formation at the top bowl or other ridges above 7500 feet).

Next we want to know what the weather will do tomorrow. There are many resources at your disposal, but I recommend for starters this one: click into Western Idaho, and follow up with another click in a smaller map over to the NE of Idaho City, above the "d" letter in Idaho City. Use the topo map window to refine the forecast for the area of interest (for our case Pilot Peak Summit). Proceed to click the "Hourly Weather Forecast" below the map window.
This forecast is for tomorrow and corresponds to the general area of Pilot Peak Summit. The precipitation forecats predicts ~9 cm of overnight snow with a slight cooling trend.  The temperature forecast shows a coling trend during the day. The sky cover forecast is for the sky to open up before noon. Winds are forecasted to be low-moderate from the NE.

There are other weather resources,  ...  a truckload of them, and too many to list here. I recommend always to read the forecast discussion from NWS-NOAA and browse this site;

WOW, in what it might take you less than 30 minutes by yourself, we demostrated how to improve SA by reviewing snowpack and weather resources. These resources allows us lean about the current Avalanche Environment at MCS. Let's make sure consider the MOST relevant data;
  1. A possible total of 20 cms of NEW snow precipitating in a reactive snowpack with a "persistent slab" problem type.  How the risk of triggering avalanches and consequences are impacted by new snow in top of an unstable snowpack?
  2. Colder snow above warmer slow - this good for skiing conditions!
  3. Thursday snow might have a surface crust at lower elevations (~ below 7000 feet) separating the new snow predicted for tonite (Friday night). Is it possible to find a shallow storm slab problem tomorrow at MCS?
  4. Moderate winds from SW shifting to NW. New snow available for transport. Where can we find wind slabs?
  5. The total snowpack at MCS Snotel by tomorrow might reach tomorrow 80 cm, well below average. Snow coverage at lower elevations slightly improving, but what are the risk of underbrush and deadfall?
  6. Visibility improving with partly sunny conditions by mid-morning. An invigorating sense of happiness with a crystalline white landscape, new snow, great skiing, and sunny weather. Is it possible to deviate from a good plan due to "feel good blue ski day"?
It is not possible to cover in this posting how to develop a plan based on the above Perception of the Environment. It requires an understanding of the Avalanche Triangle (Weather, snowpack, Terrain). That understanding will enable to anticipate, a key component during the development of ski touring plans. Consider an avalanche class or refresher, where it is covered snow metamorphism and avalanche release mechanisms. Remeber that it is now possible to participate in avalanche courses at MCS! Visit SKIPILOTS.COM or AVYSCIENCE.COM for the various avalanche educational offerings.

This posting was a realistic exercise to show how much we can learn from the "avalanche" environment with online resources and tools available at smartphones We got started by asking - How we can improve situational awareness? We briefly explored the weather and snowpack for MCS. Your homework is to integrate what we learned into the MCS terrain. In other words - define where to safely travel and ski, and map it. Foremost the planning is completed when you have identified, with a map at hand (or in the smartphone/tablet/PC) where NOT to travel and ski tomorrow!

A big component of Situational Awareness is becoming familiar with the terrain characteristics such as; aspect, elevation, slope angles, wind loading areas, wind protected areas, open/heavy timber areas, terrain traps, snow-covered forest service roads, creeks, among other terrain features. The maps for MCS are available on this blog and are provided with slope angle coloring. The topo maps for Mores Creek Summit area are based on 10 meter resolution DEM source.
I have been recommending to load Avenza into your smartphones. The application allows you to draw tracks. For example, use the drawing function to denote your uphill track, as well as creating segments representing lines you intend to ski. In the field, you can compare planned versus actual track/segments. And more importantly, while in the field, if you deviate from your plan you can clearly improve your situational awareness by identifying avalanche terrain based on the map slope angles.

Get the Avenza app and maps at

You can load the free Mores Creek Summit area topo maps with shaded angles into your smartphones, tablets, or PCs at the link included below:

I intend to add other maps from Idaho to this database as my discretionary time allows. There are other terrain mapping apps for smartphones that work very well and that I also use (such as GAIA). The intent here is to make sure that the MCS backcountry community has access to the basic tools necessary to integrate SA into ski touring.

An aspect we did not cover here is the Social Environment. Tha HUMAN element is key in the formulation of a plan. I will do that in a future posting. Touring/riding skills, avalanche terrain travel experience, attitude, health, gender, risk acceptance, and personality can interact positively or destructively during development and execution of a SAFE ski touring plan.

Wednesday, December 27, 2017

Almost Top of the World - Snowpack Assestment

You know the snowpack must be treated with respect when whumpf (collapses) are widespread. But then, when skinning through small terrain features (safe areas) and small releases are triggered, it becomes poignantly clear that the snowpack has a weak structure prone to fracture propagation.

I was surprised when climbing up to Pilot Peak I triggered multiple collapses at south aspects above 7200 feet. I was NOT expecting that south aspects will have a weak structure.

The next videos show the compression, extended column compression test, and an experimental horizontal saw test.

CTM_12_27_2017 from Santiago Rodriguez on Vimeo.

ECTP_Dec27_2017 from Santiago Rodriguez on Vimeo.

H_PST_Dec27_2017 from Santiago Rodriguez on Vimeo.
Both compression tests failed at moderate scores and provided further evidence of fracture propagation propensity, in addition to collapses and cracks observed today.

The last few days I have been carefully observing test results for various stability tests. Two days ago and today, the Propagation Saw Test (PST) fracture was arrested after the slab broke, as it can be seen in the two pictures included below.

I do not think it is an issue related to slab stiffness or aspect ratio, the bending moments resulting from the propagating wave are sufficient to mechanically disturb the slab and break it. I tried different aspect ratios and widths with no success. Besides, avalanche researchers have documented that the PST can be unreliable with thin slabs.

The snowpit profile changed very little from two days ago.

Notice that today I measured crystal sizes. I was unimpressed with the facet lack of striations, and irregular crystal sizes and shapes of the facets. However, I noticed significant facet chains. As I drove back to Boise I kept thinking how to document that attribute, and I have an idea I will test in a day or two.

The temperature gradient at the weak layer interface in the snow pit profile is not strong. It is unlikely that at this time there is any significant active facet metamorphism at the weak layer interface. Today's snow pit, just like the one two days ago has a thin ice crust, that can be easily missed.

With regard to the snowpit data - One trick I use to make easier recording snowpit data is to take a picture with the hardness marked at the snowpit side walls. Check the fist, 4-fingers, and 1-finger indentations in the next picture:

The skiing was fun today, but the snow has densified compared to two days ago.

AlmostTopWorldDec27_2017 from Santiago Rodriguez on Vimeo.

Snow settlement is driven by the effect of gravity on the snow - its weight causes densification. Sintering metamorphism is responsible for the building of bonds between snow crystals. Snow settlement and sintering inevitably result in the development of a slab. And there is a weak layer with facets in excess of 2 mm in size under the slab. We call this avalanche problem a "Persistent Slab" problem. The term persistent refers to the temporal durability of the facets undermining the slab.

Meanwhile, there is a winter weather advisory for Thursday night through Friday with a potential of up to 20 cm or more of new snow. The snowpack structure at MCS is a concern, thus it will be important to apply conservative decision making during the upcoming weekend. An important practice during periods of instability is to be aware of slope steepness. There are two tools that make easier to travel safely; a topo map with slope steepness and a clinometer to measure slope angles.

During the last posting (Christmas day), I encouraged blog readers to install on their phones the free Avenza application. Also, you need to use the Avenza app to download into your smart-phone the maps for Pilot, Freeman, Sunset, Wilson peaks. These maps are available at the Avenza map store for free. I uploaded to Avenza database several georeferenced pdf maps with colored slope angles for MCS area as well as Copper Mountain - Banner Summit. Below an example of the application with today's (blue track) as well as December 25 tour (yellow track) tour.
Notice that red denotes terrain steeper than 35 degrees, and that must be considered avalanche terrain. This solution replaces a printed topo map, and it is a fantastic safe travel tool - Why? - It will display where you are relative to steep terrain.

But we also need to measure slope angle in the actual terrain. It is not possible for maps to capture small terrain variations that result in avalanche exposure. I suggest that you purchase a phone app named "Avalanche Inclinometer". It is only a few bucks, it is the best app out there, and it works. I have compared the app it to a forestry (accurate) clinometer and it compares very well.

There are various phones apps for slope angle measurement. But the one recommended here has a feature that makes it the best solution. You basically sight the angle through the phone long axis side and a simulated voice dictates the angle. You can use your finger to tap the screen to lock the slope angle measurement if you do not want to use the voice option. I have not seen any other inclinometer app that locks the clinometer after sighting. That feature is a MOST. The color of the screen reflects the if the angles correspond to avalanche terrain danger (Red = High, Orange = Moderate, Green = Low).

My day finished on a high note. On my way down I met some very nice folks snowshoeing at Pilot Peak. It is terrific to see other users enjoying travel in snow!

Tuesday, December 26, 2017

Christmas Day 2017 - Good Pow and Unstable Snowpack

This is not an average snow year, at least so far. Even without perusing into the NRCS-Snotel reports for Mores Creek Summit we are behind snow amounts this winter. Throughout the years I developed a rule-of-thumb to start backcountry skiing at MCS when there was more than a meter of snow at the MCS Snotel. I broke the rule yesterday, with a reported snow depth of 66 cm at MCS snotel.

Skiing was fun above 7000 feet, with a somewhat unconsolidated snowpack at spots. Turns were sweet with fast pow skiing conditions.
Below 7000 feet you had to pay attention to what might be lurking below the snow surface. I was very careful and still one of my skis managed to get snag when it got caught in deadfall but it fortunately easily released. Be careful, the snow cover is shallow below 7000 feet, and last year's Pioneer fire left a lot of fallen burnt trees.
What about the snowpack? The snowpack was definately unstable. This was not a surprise considering the extended dry conditions during December that allowed near surface facets to develop.

It was easy to find evidence of instability. There were multiple crown fractures from avalanches released during the last storm, and plenty of surface cracking with whumpfs. Quick "hand-compression" either failed during isolation or easy collapses when tapping the column.

The depth of the instability varied from 20 to 30 cm from the snow surface to the interface between the new snow and a well-developed facet layer. At the interface, between the new snow and facets, there was a fragile crust layer - which is definitely not good!
At ~7200 feet in elevation a snowpit with NE aspect and 28° slope angle was 63 cm deep (HS). The new snow layer was fist hard with a layer thickness of 21 cms. There was a thin crust layer between the new snow and facet layer insterface.  The facet layer under the crust was 9-10 cm thick. Below the facet layer there was a 25 cm thick pencil hard layer of rounds. Fracture failures were ocurring at the top of the facet layer, right at the crust to facet interface.

You can access the snowpit profile at:

I recommend using saving SnowPilot website and database to generate and save your snowpit profiles. SnowPilot web based application is free and it is based on AAA SWAG standards. Sharing your snowpit and avalanche observations you will advance Snow Science since the data is used for research, while at the same time you are refining your snow, avalanche, and weather standarized nomenclature.

Extended columns stability test failed consistently with easy scores. Check the next two links for short videos of the extended column stability tests:

Compression Extended Column Test

Extended Saw Column Test

The snowpack at MCS has a persistent slab structure. This instability will be with us for a while. The faceted layer is well developed with a thickness of up to 10 cm. As the new snow sinters and further develops into rounds, the reactivity of this avalanche problem will decrease. Be mindful of the existing snowpack weak structure at MCS, this a rare event, and it has been more than 30 years since MCS had experienced such a low SWE water year.  Since this is a rare event, we do not have experience with this conditions at MCS. At the same time, persistent slab conditions tend to be unpredictable and easily propagate across distances, significantly raising the consequences when caught in an avalanche at slopes with terrain traps. And the bad news is that MCS has many terrain traps, plenty of steep creek bottoms and fun treed terrain that will become a nightmare if caught in a slide.

The coverage is still poor as you will see in the pictures included below. Let's keep the fingers crossed for the next storm arriving tonite. The forecast is not too encouraging with respect to precipitation amounts, but surprises do happen.

For those interested in downloading into their phones topo maps with "colored" slope angles, you will find in Avenza a collection of FREE maps I made available for MCS where you can overlay your track while touring. It is a nice tool to get an idea of slope angles while touring or skiing.

Below a sample of the Avenza application screen. Avenza is a FREE smartphone application where I am providing FREE georefenced maps for popular backcountry skiing destinations in Idaho.

You will find at AVENZA MAP Store, topo maps with colored slopes angles for Pilot, Freeman, Wilson, and Sunset Peaks. There is also a "colored" slope topo map for Copper Mountain at Banner Summit.

Finally, I wil be uploading into GAIA tracks from tours at MCS.
With the GAIA tracks you will find pics of snowpits, instability signs, or other relevant information. Check the track for yesterday's short tour at:

Gaia Track for Summit Creek Tour - Christmas Day 2017

These two GPS tracking apps (GAIA and Avenza) are good tools that further improve terrain situational awareness.