Northern San Juan

Avalanche

Caleb Leland · Jan 8, 2019 · Northern San Juan

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Weather

Location: Dry Gulch Aspect: E, SE Elevation: 12,000' Sky: FEW Precip: NO Wind: Light - S, SE Extent of Blowing Snow: PREV Temp: 30 degrees F

Snowpack

-Evidence of recent wind loading from storm on 20190106 - 20190107 -Small pockets of Hard Slabs observed on SW aspects ATL. Dissipated NTL -Large snow deposits from recent wind loading on N, NE, E, SE aspect of Dry Gulch. Wind slabs observed adjacent to ridge line and downslope from ridge. -Numerous recent natural avalanches observed on Mcmillan, Anvil, Bonita and others. (20190107) Storm snow from 20190106-2019017 was cold, low density, (F) hardness. Observed 12" in the parking lot, upwards of 18"+ at 12,000'. Recent storm snow fell on melt/freeze crust from warm temperatures earlier in the week. Crust facet combinations found below most recent crust to the ground. Toured same area day prior (20190107). Observed several localized collapses, no propagation or shooting cracks. Descended SW aspect back to CR 35. (20190108) - Recent storm snow had settled significantly. Hardness remained (F). Temperatures increased rapidly and recent storm snow began to transform. No longer cold or low density.

Avalanche

HS-ASr-R2-D3-I As we approached the ridge line separating prospect gulch from dry gulch we observed a very loud collapse. Moments later the avalanche fractured approximately 150' - 200' downslope in dry gulch. From the ridge line we could not identify how much terrain was entrained in the avalanche, however a powder cloud was produced and we observed the powder cloud hit the gully and turn the corner out of sight. From the ridge line we could make out large chunks of debris. We estimated the crown depth to be 3-5FT. Due to the location of the avalanche we were unable to obtain dimensions on how wide the crown of the avalanche was. From Gladstone we were unable to tell how much area was entrained in the slide; all that was visible was a vey small portion of the crown of the avalanche. Avalanche appeared to run on the new snow/old snow interface but again had no way of viewing bed surface from the ridge. Similar to the previous day, we descended via SW aspect back to CR 35.