23-24

Large surface near Little Bear. Photo: JR Mooney

Massive surface hoar on sheltered slopes outside of West Yellowstone 

We rode onto Tepee Basin and saw little change since the last time we were there on December 13th (see that here). What we did find is that the snow has become more supportable in some areas but the poor structure remains. In our stability tests we had low scores on both northern and southern apects, with ECTP11 and ECTP12 results on facets below early December snow. The snow near the surface has begun to facet and surface hoar can be found on many slopes. In some areas this surface hoar was large and rimed. 

As the snow returns areas with this poor structure will increase in danger. As the amount of snow increases so will the possibility of triggering an avalanche. 

Skiers on 12/21 saw 2 old avalanches while skiing in the Divide Peak Cirque. These avalanches likely happened near the end of the last storm cycle, 12/9. 

From obs: "Saw evidence of two natural avalanches on southwest aspects (see photos). The age of these slides was hard to gauge based on our lack of recent snow."

Total snow depth 60cm

EctP16@22cm   South Aspect @7800ft

Toured into Divide Basin yesterday (12/21). Saw evidence of two natural avalanches on southwest aspects (see photos). The age of these slides was hard to gauge based on our lack of recent snow. I toured to a south aspect adjacent to the south face of Divide Peak and dug a quick pit. Snow was ~65 cm deep. I did an ECT and got an ECTP3 failing on a facet layer overlaying a finger hard crust 31 cm down. Below the crust was fist hard facets to the ground. 

I decided to check out some other aspects in the basin. On the majority of shady aspects I found a uniformly weak snowpack and frequently sunk in facets to above my knees while touring. On aspects with supportable snow I experienced frequent and widespread collapsing.