Top of Moonlight 070317

It appears that spring has sprung in the Cascades with free air temsps at 11.2 C. Hopefully it will cool down and we will get more glorious powder before it is really too late.

Although it was only a test pit, I took a number of temperature observations.

Surface- 5.3 C

20 cm - 0.9 C

40 cm - 0.8C

60 cm - 0.7 C

80 cm - 0.6C

100 cm - 0.6 C

120 cm - 0.6 C

140 cm - 0.6 C

For all intents and purposes this can be considered isothermal.

I had difficult determining layers and crusts, and to be honest, should have paid more attention to the crusts, elusive though they were.

I did not however find any real weak bonds, Compression Test yielded nothing and attempts to pry apart the snow column provided a very low quality shear near 100 cm which I believe had no bearing on anything, since this was not a real Shear Test.

We did notice numerous sluffs of the top 5 cm.

Also noteworthy was the difficulty of making crystal observations in the warm air and sunlight.

Top of Yodlin 070224

I was rather suprised to find that the new snow from this week was firmly bonded to the old snow that fell in early January and was the surface for almost a month. At 84 cm was the transition and the bond was so solid that I could not kick it, pry it or otherwise seperate the layers. I was not expecteding this to be the condition. Was also suprised to find that there was a suncrust at 13 cm, in fact I missed it at the first go around. This was where we saw much sluffing. The north side of the ridge did not have the crust (of course).

Additionally, I was playing around with my density kit and found that we had 7% moisture snow in the top layer ( 35 g in 500 ml tube = 70/1000 ml or 7/100 or 7% as I figure it). Pretty good for the PNW.

Also the time was 1240, not 2038 as the profile says. I am still having trouble with the time in snowpilot..... oh well.

Bear Gap 070120

Dug a pit to the depth of 135 cm on a SE slope on the top of a convex roll in the Crystal Mountain Backcountry.
Was not particularly reactive. Based on the snowpack history (some warming, some very low temps, a bunch of wind in places) I believe that the snowpack is extremely variable and liable to be very different from one aspect to the next, as well as geographic variation of a only a few miles.

Yodlin 061223

A most interesting day out there.
Two noteworthy issues, first was a tempature gradient.
At 10 CM -3.9 C
At 20 cm -5.7 C
After that it became more normalized 0.2-0.3 C every 10 cm

The second and perhaps more important was a clean, high quality shear at 160 cm, yes that was 160 cm with a CTM with a score of 19. Now that is scary and pretty remarkable. That layer seems to be pretty well bridged right now, but if something changes it could get really ugly, really ugly. I would suspect that is is isolated in pockets and it would take a huge warming cycle to make this happen.


I am still getting the hand of the new Snowpilot software and there are a few errors that I need to figure out how to fix. I also have a few wish lists in terms of what I would like to see this software do. But it is a hell of a lot prettier than my fieldbook.

Rutschblock explained

Until last week, I had neglected to include a Rutschblock test.
First and foremost, this strikes me as odd, since it is my favorite test. For the uninitiated, this test is a continuation of your test pit, which is extended across the slope 2 meters, it is then cut back about 1.5 meters on either side and then the back is cut down to the same depth of the slope.
If a layer goes at this point it is considered a load of 1.
Next a skier gingerly stands on the top of the block, if it fails at this point it is a load of 2.
Then the skier makes some knee bends (partly weighting and unweighting the skis. If it fails here it is a 3.
The skier then jumps once, if it fails here it is a 4.
The skier then jumps again, failure at this point is a 5.
The skier is then replaced by a pedestrian jumping or stepping down to mid-block on skis and jumping some more, a failure here is a 6.
No failure at all is a 7.

I remember the rating scale as “Jump 4 joy” since a jump is a 4, and you are starting to get psyched once you get to a 4, a good little memory tool.

The summary in the OGRS is that a 1, 2 or 3 is unstable.
A score of 4 or 5, a slope is pretty suspect.
A score of 6 or 7, the risk of a skier trigger avalanche is considered to be low on that slope and possibly other, similar slopes.

This is a great test since it approximates the actions of a skier better than any other stability test other than a ski cut and it is fun and a good way to warm up after recording data in a hole in the snow. It is far from perfect and like all the other pit tests, can only be assumed to be 100% accurate for the immediate area of the pit, since we all ski slopes larger than 1.5 meters we need to evaluate the results of this test carefully and be sure that we do not over generalize.

Back to the reason for my omission of this test, a slope of at least 25 degrees is needed and 30 is greatly preferred. Another wacky rule of thumb is to subtract 1 for each 10 degrees of increased slope. For example a score of 4 from a test site at 32 degrees would translate to a 2 on a 52 degree slope nearby, which is a good rule if you can dig a safe pit on a 25 degree slope and can’t safely dig a pit on the 45 degree slope nearby which you want to ski if the results of your snow analysis are favorable.

Bullion Basin, Crystal Mountain 061202

I was very curious to get a look at the structure of the snowpack, since it has been an interesting week for Washington State weather, with heaps of snow and very cold weather. Since I was traveling alone, I was very cautious about which slopes I was willing to travel on, let alone to ski.
I chose to dig a pit in a less than ideal spot at 5370ft. It was closer to the trees than I would have liked but I did not want to stop in an avalanche chute and was hyper aware of the sun hitting the steeper slopes above me. The pit itself was a great learning experience for me and I made some errors.
It was the first Rutschblock test and the first Shovel Shear test of the season, both of which were done incorrectly. I will update that a little later in the week about how they were done and how they will be done in the future.
I found some nice hoar frost, which melted later in the day. Also, I found fairly cohesive snow bridging the weakness of the rain crust at 27 cm. In the upper layers there were a couple of failures with a RB4 at 112cm and 126cm, neither of which concerned me much and were stiffening up as the day went on.
I dug a hasty pit at 6400 ft with an E expose. It showed even stiffer snowpack at about 120 and less of a crust with greater cohesion. The sun was also further consolidating the surface snow. I skied this exposure all day without incident.
Perhaps most interestingly, at least 25 people passed within 5 meters of me doing my full observations, only three two stopped to ask me what I had found. This is a bit distressing. Thanks to Troy for helping my on my Rutschblock.

Whitewater Ski Area 061125

Since the ski area was closed, I figured it was fair game to ski up and dig a full pit, which is getting harder to do with a snowpack of 156 cm at that spot.

Steven's Pass Observation 061118

Yesterday’s sortie to Steven’s Pass was great in terms of snow science, but awful in terms of skiing due to a mean breakable crust.
The observations took one hour, based mostly on my rustiness since it has been almost 4 years since I last made and recorded a proper observation. In layman’s terms there is 7 cm of cold snow on top of a hard crust made by the rain event late last week. Under this layer, it was a Very Easy Shear when the column was isolated for a compression test. This elimated the need for a Rutschblock or a Shovel shear test. The rain crust was very strong and acted as a good bridge over this weak layer. I would expect that the rain and warming that occurred last night will further strengthen the rain crust at 1 meter. Also noteworthy is the column isolated under this layer (the bottom 100 cm of snow) was extremely strong and was removed from the pit in a single heavy column. Below is my Snow profile.

Moist snow on the Marsh

It is about time that some snow fell on the soggy ground. I have been studying the OGRS as it is called and getting ready to dig some pits.

Why are you doing this?

Although I have been enjoying the winter time activities of the Pacific Northwest for years. Have yet to give back all that I should.
A couple of years ago I took the Canadian Avalanche Association Level I class, and have yet to put much of it to work. This winter I endevour to post twice weekly in order to improve my skills and to share with the ski community of the Cascades.