20-21

Skied Mt Blackmore this morning. Very windy up in the basin, but calm along the ridgeline. Lots of signs of wind-loading and drifting on most slopes.

I felt/heard 3 collapses while ascending the trees up to the east ridge. Saw a debris pile on the N face, likely from a cornice fall in the last 24hrs. Stayed low angle in the trees on the way down, and triggered a few 1-2" thick wind slabs on isolated features while skiing out of the basin.

Skiers triggered a wind slab while ascending the north couloir on Abiathar Peak on 1/2/21. On their descent they triggered this similar sized slab. They were not caught or injured, and felt lucky to dodge a bullet. 

This morning I was ascending Flanders Peak via the southeast trees. At approximately 10:30AM, 9500 feet elevation, we dug a pit (photo attached) and was surprised to get a ECTN. However, we did make notes of a buried solar crust between 51-60cm (1F) and a basal crust (P) on the first 5cm of the pit with the same large, sugary facets we've seen all over the Bozeman area sandwiched in between these two layers that supported our plan to stick to low angle slopes. At approximately 1:30PM, on our second lap of the south-southeast bowl of Flanders Peak, I was skinning behind my friend who was putting in a new ascent track when we both heard a large "whump" and a 15 foot crack shot out from under his skis. I also witnessed him drop several inches from the large collapse in the snow. We were on a very low angle slope (less than 25 degrees) at approximately 9700 feet, in wide open trees right at the edge of tree-line and the alpine. We noticed no other signs of instability in the bowl we skied, or on the wind-loaded ridge. We decided to not keep lapping the bowl after this happened but instead skied back to the car.

Skiers triggered this slab while ascending the north couloir on Abiathar Peak on 1/2/21. On their descent they triggered another similar sized slab. They were not caught or injured, and felt lucky to dodge a bullet. 

Quick observation from some exploratory skiing in the Crazies today. Toured in from Cottonwood Creek and followed a lower angle shoulder to gain the ridgeline between Pauline Creek and Little Cottonwood Creek. A bit schwacky down low and quite faceted. Found supportable skiing above ~7800' all the way up to the wind scoured ridgeline at 9300'. No recent avalanches, collapses, or cracking observed, aside from a couple of small predictable ~3" thick fresh wind slabs near the ridge top.

Temps hovered around 20F all day with moderate WNW winds that died after 1pm and variable cloud cover (overcast one minute and blue skies the next).

Snowpack was ~70cm deep (on average) and had 15cm of new/decomposing snow sitting on a mostly supportable 4F+ layer of rounds above a mix of F facets and a decomposing melt freeze crust. Quick pit @8350' SE 28* slope - ECTN10@55cm on hardness change (new snow) & ECTP14 (and ECTP21) @35cm on facets above the melt-freeze crust. To mitigate the persistent slab problem, we kept it low angle and avoided areas we predicted would harbor more cohesive/connected slabs.