Northern Gallatin

Toured up into Blackmore basin this afternoon and skied the SE Shoulder. Moderate winds from the north were transporting some snow, but I was surprised by how calm it was up there. Small cornices had built up on the shoulder. S-1 snowfall beginning at 2pm and increasing as I skied out. The coverage is amazing - nearly tree skiable in the forest and HS on the shoulder around 9650' was 160cm. Top 100cm was F-1F hardness; bottom 60cm were weaker, faceted grains. I saw no cracking or collapsing. 

The one thing of note was a recent avalanche on the north face of Blackmore. Visibility was poor but it was a small pocket in a steep, rocky zone that broke near the ground. 

Seeing if the anti bot works ok.

We toured into some mid-elevation skiing in the N Gallatin on Wheeler Mountain. I was surprised that we weren't getting collapsing, given the recent loading, but, at the end of the day, I only heard one localized collapse.

The big message from the day was touchy surface conditions. When the storm abated in the afternoon, there was 9" of new snow. The most recent pulse of snow came in upside down, and we observed cracking in the top 9" every time we moved into slightly steeper terrain. We saw one R1-D1 natural avalanche on a ~35 degree slope (this was the steepest terrain we visualized today). The slide broke 15-20' wide and ran less than 50 feet. This storm slab instability will heal relatively quickly, but I expect to trigger D1 and 2 avalanches on most steep terrain today and maybe tomorrow. 

We tested the deeper weak layer with an ECT at the top of the meadows (ECTP25). Again, I was surprised by the lack of evidence of deeper instability. I wouldn't trust it until we get a few more data points and we get some visibility to assess avalanche activity. 

Little Ellis now has (barely) enough cover to be skiiable (at least up high - still marginal lower down). Dug a pit on the NE aspect 100 yard NE of the summit. Found unconsolidated snow all the way down to the ground (roughly 36" deep). Negative ECT. 

Quick late day trip up to Goose creek meadow to check coverage. OVC sky, L wind, S. Limited vis. HS 60-80cm at ~7400'. Probing showed a very weak pack, weakest below the last week's snow. Some prev wind redistribution, areas of 90 cm. 

Collapsing, localized. 3 audible collapses when poking around well off trail and in unskied areas~7300'. ENE aspect off ridge. 2-3m radius, HS 80+. Seemed to need some prev loading to show instability. No time to investigate but likely collapses were between the last week's snow and  the Dec drought layer, which probed very weak.

We observed many large whumps and shooting cracks while headed up the meadows of Cinnamon mountain today, several of which were large enough to shake nearby saplings. These collapses were likely triggering on the recently buried layer of basal facets. Conditions included warm temps, light SW winds, overcast to obscured cloud cover, and S-1 to S1 precip including steady graupel. Nothing particularly surprising considering the conditions in nearby areas, and we chose to keep our terrain choices conservative.

Skied Maid of the Mist today. The only avalanches seen were small (<10ft in length) loose snow releases directly below small trees on north facing 35+ degree aspects at 9200 feet. Poor visibility generally limited views to a few hundred yards. A small amount of stiffening from wind was noticed on the snow surface on the way out of the basin, but there was little to no wind effect in the trees on the south side of the Maid. Ski conditions were fantastic.

Around 7 p.m. Monday night, a few miles up Portal Creek, triggered from bottom of slope.

Around 7 p.m. Monday night, a few miles up Portal Creek, triggered from bottom of slope.