A couple weeks ago I had Suzanne in my most memorable AIARE 1 Avalanche Course to date. She had just entered the floor of the ravine with my co-instructor Mike when we witnessed a climber triggered avalanche that caught 5 people and injured two. As a doctor she was quick to volunteer to help US Forest Service Snow Rangers evacuate one of the victims.
This incident prevented her, and most of the class, from being able to make snow-pack observations and she was keen to return to the ravine for some more experiential learning. Yesterday she returned and this time she brought her energetic 20 year old son Jabus and friend and long time NH climber David to join her in the experience.
Since ski conditions were quite abysmal we opted for mountaineering boots & crampons and brought a little technical gear along to deal with the hard & fast sliding surfaces that make up most of Tuckerman Ravine right now. After a trip planning session we made our way up into the bowl and headed up into Left Gully to investigate some of the wind slab that was mentioned in the morning’s avalanche bulletin.
The climbing conditions were quite firm, and with caution & focus we reached the base of Left of Left (ice climb). After a short break we traversed right into the gully proper and I moved out onto a moderate sized slab that had formed from cross-loading over the last two days while everyone else spotted me. Hand shear tests along the way broke with moderate force and were not very planar so I moved to where the slab felt a little deeper and dug a quick pit.
Finding about 15cms of Pencil hard slab over 15cms of 1-Finger snow, sitting on top of Knife hard concrete we carried out 3 quick sets of tests.
Two Shovel Tilt Tests, one which was “positive” and one that was “inconclusive” at the 15cm interface. For a quick description of the Shovel Tilt Test check out this video from the Utah Avalanche Center:
Two Compression Tests:
CT11, Q2 RP @ 30cm down (interface of 1F & K concrete)
CT11, Q3 BRK @ 30cm down (interface of 1F & K concrete)
Wanna watch some more YouTube on snow pack tests? Here’s one on the Compression Test:
While these failures were on the eye brow raising end of loading steps, the “shear quality” or “fracture character” was not very alarming. None-the-less we decided to carry out an Extended Column Test to increase our confidence in our findings.
Results: ECTX (No fractures are initiated in the 30 standard loading steps)
Before you ask here’s a pretty good video of the Extended Column Test:
Before descending I grabbed a quick shot looking up the gully…
And down the gully…
We descended to Hermit Lake and removed our crampons for a faster hike down to Pinkham Notch.
Back at the pack room we debriefed our trip into the alpine and parted ways. It was a pleasure to spend this time in the mountains with Suzanne, Jabus, and David and I’m looking forward to our next trip together.
A quick disclaimer regarding these YouTube videos I’ve posted. These should serve one of two purposes:
- Inspire you to take a course to really learn how to perform and interpret these tests.
- Refresh what you’ve learned from a formal course
Using YouTube videos to build your base knowledge could lead to… less than ideal results. But they are great for refreshing those skills!
Thanks for reading,
See you in the mountains,