Northwest Avalanche Center - Public Observation

Name:

Enji Cooper

Observation Date:

March 27, 2021

Submitted:

March 29, 2021

Zone or Region:

East Central

Activity:

XC Skiing/Snowshoeing

Location:

Tronsen Ridge/Meadows

Did you observe any avalanches?

Yes

Comments:

Observed a variety of wet loose avalanche debris, ranging from D1 (along the ridge) to D2 (Diamond Head), around the Tronsen Ridge basin on northern aspects. One instance we were able to look at seemed to be trigger by an increase in temperatures on an NE facing aspect of the ridge and was part of a cornice.

Also triggered a lot of wet loose debris (melon-sized pinwheels mostly, but some fist-sized rollerballs) that ran for 50' or so in our down track route.

None reported

Started off early from 47.3378, -120.5664. Proceeded along NF-7420 and pushed N up lower angled ridge to Point 5367. Much of the ascent was snow free up until Point 5367 along W facing slopes (we stuck to game trails and more durable surfaces wherever possible). Point 5367 had some ice and low coverage snowpack.

The saddle between Point 5367 and Tronsen Ridge "Peak" (Point 5575) (47.3392, -120.5366) was snowier, but didn't exhibit any major instability concerns.

The saddle/ridge spine up from Point 5575 to Point 5940 (47.3341, -120.5304) was where we started exercising caution due to large cornice overhangs and visible/anecdotal instabilities between the top-layer of wind fetch (approximately 3"~6" deep) and the lower, more consolidated/icy layer.

At higher elevations between Point 5940 and Tronsen Head, we encountered variable snow coverage: some areas were bare/exposed rock -- other areas were deeper fetch in the saddle/under the trees (where it was more shaded). Down lower, the snow was more consolidated/firm earlier on in the day.

Getting up the ridge from the saddle to Tronsen Head was more difficult due to non-consolidated dry-ish powder (wind fetch/storm snow), but I didn't observe the slab breaks I had seen near Point 5940.

Getting down from Tronsen Head to Tronsen Meadows involved a down track starting near 47.3126, -120.5452, heading approximately due N (this area was chosen due to slope angle/higher tree cover). We accidentally went a bit too far skier's left in areas running into slope angles greater than 35°, which forced us to course correct (skier's right) to lower angled slopes (much of what was observed here was D1/R1 wet loose debris). Once we got down to approximately 5200', the risk was reduced due to lower slope angle and less wind fetch.