21-22

Toured in the Flints this weekend on all aspects between 8-9k ft. Solar aspect had begun to develop a melt freeze crust. Consistent SW winds effectively transported the foot of low density snow which had fallen over the last week. Prevailing winds swirled off ridge tops and had begun to effect leeward slopes scouring and drifting below treeline. Above treeline, alpine slopes were primarily scoured with significant drifting noted in some leeward alpine basins. No significant signs of instability observed aside from isolated cracking of wind slabs on ridges.

Toured in the Flints this weekend on all aspects between 8-9k ft. Solar aspect had begun to develop a melt freeze crust. Consistent SW winds effectively transported the foot of low density snow which had fallen over the last week. Prevailing winds swirled off ridge tops and had begun to effect leeward slopes scouring and drifting below treeline. Above treeline, alpine slopes were primarily scoured with significant drifting noted in some leeward alpine basins. No significant signs of instability observed aside from isolated cracking of wind slabs on ridges.

We noted no signs of instability between Hylaite peak and Mt Bole (we conducted quick hand pits and shovel shears along the route). There was a large cornice collapse on an east facing ridge to the west of Divide Peak (photo) and, with sunny weather in the afternoon, we watched out for large overhanging cornices that were getting backed in the sun (photo). On the northeast face of Elephant Mountain, at ~9850ft, we recorded a  sudden planar Q1 shear with easy effort @15cm in a shovel shear test (photo). Although this site was in a small, isolated pocket of wind loading, we will be watching this layer closely going forward. 

A completely sugary faceted snowpack on an east facing slope above the Texas Meadows Knob to the west on an East facing aspect. Extremely week all the way through consistently at this elevation. Scary for future loading.

We skied south of Quake Lake today, and found stable conditions. I observed one collapsed cornice from several days ago that had tumbled down a ~35 degree, east-facing slope at 9400' without triggering anything below it. A pit at ~8400' was 115 cm deep and showed a pretty thoroughly rotten, weak snowpack. We found no reactivity in an ECT, but I could get a shear about 15 cm down on a 1-2 cm layer of lower-density facets. We felt comfortable traveling and skiing in avalanche terrain, but the snow is so faceted near the surface that it can be difficult to sidehill on anything steep--the top of the snowpack feels more like sand than snow, and skis like it, too. I encountered similar conditions skiing above Hebgen Lake yesterday, and anticipate this snowpack to be reactive if it ever snows again.

We found an overall very variable snowpack in the alpine, with deeper wind affected snow on leeward features, usually sporting a thin to moderate wind board and very shallow, hard wind affected snow on windward features, usually rocky. Below and near tree line, snow was soft and cold on northerly aspects and a bit squishy and warm on more southerly slopes. In the couloir it’s self, we found a shallow snowpack averaging 30-70 cm in depth. Lower in the couloir we found a 6-8cm faceting crust over large facets. It was not reactive to non-SWAG hand pits and shear tests dug throughout the up route. Higher (approx 1/2 the way) in the couloir, the snow transitioned to rounded, hard to very hard (1F to P, some places P+ or K) wind affected snow uniform throughout the depth. This only changed on the more southerly parts, often near rock, where the snow was faceted and softer (4F to F), being unconsolidated and loose in a few places. 

Graph of Snow Water Equivalent (SWE) at SNOTEL sites in the GNFAC forecast area from October 1, 2021 to January 30, 2022. It highlights the extended dry conditions in January that contributed to weak layers forming at the top of the snowpack. GNFAC