Headed into Blackmore Basin today planning to keep it low angle and to see the effects of recent snow and wind. Moderate winds with strong gusts were transporting snow the entire day, and a stout windslab was widespread. All previous tracks on the main SE facing run were completely filled in. Asides from the wind transport and some small natural cornice drops I noticed no other major signs of instability, but still kept a solid margin from avalanche terrain.
<p>Heightened avalanche conditions exist. Human-triggered <strong>persistent slab </strong>and <strong>wind slab avalanches </strong>are possible. Over the last three days, light snowfall across the advisory area added up to 5” in Cooke City, with a trace to 3” elsewhere. Incremental loading gives us pause but is not likely to increase the avalanche danger outside of specific slopes where drifts of wind-loaded snow are thicker.</p>
<p>Recent drifting makes <strong>wind slab avalanches</strong> a hazard on specific terrain features and exacerbates persistent slab instability. Avoid steep, commonly wind-loaded slopes near ridgelines, below cornices and upper-elevation gullies to reduce the likelihood of triggering both wind slab and persistent slab avalanches (<a href="https://www.mtavalanche.com/images/24/cross-loading-henderson-mountain"… 1</span></a>, <a href="https://www.mtavalanche.com/images/24/cross-loading-miller-ridge"><span…;). Visual clues of recent drifting, a stiffening of snow surfaces and shooting cracks are signs of potential instability.</p>
<p>Appropriate terrain selection is the solution to today’s avalanche problems. Selecting slopes less than 30 degrees steep without overhead hazard largely eliminates the risk of avalanches. Along with safe travel practices, good partners, and rescue gear, selecting lower-angle avalanche terrain sheltered from the wind with fewer terrain traps reduces the likelihood and consequences of a slide.</p>
Despite a couple of recent observations stating that Bacon Rind could use more snow, we decided to try it. Perhaps we should have listened. Total snow depths ranged from 15 to 24" (39-61 cm in our snowpits), or in shorthand... not enough snow!
We toured up to the top of the Skillet in the northern of the two primary Bacon Rind areas. The thin snowpack was primarily comprised of weak, sugary facets with a thin soft slab (Fist to 4 Finger hardness) on top. In 2/3 of the upper elevation snowpits, there was a layer of feathery surface hoar buried on top of the facets and below the soft slab. Snowpack tests generally indicated instability (ECTPV, ECTP3, ECTP11, and PST 20/100 end).
While we chose not to roll the dice, the slab was thin (7" thick maximum), and we observed indications (slab qualities) that an avalanche most likely would not break widely across a bowl. HOWEVER, similar to what Alex and I saw at Lionhead the day before, it won't take much new or wind-drifted snow to change the equation, driving the avalanche danger up and making avalanches large enough to bury or injure a skier or rider likely.
For now, it seemed that barely buried logs, stumps, and rocks were the greatest hazard. Once it snows enough to change the skiing quality meaningfully, I will worry about recreating on terrain steeper than 30 degrees due to avalanches. 0.5" of SWE would drastically change the picture.
We ski toured in Sheep Creek today, north of Cooke City. Of note, a thin (4mm) rime crust was forming due to the high humidity/ quasi rain. Remarkably the rime crust skied very well. Photo: B. Fredlund
