Quick report
Minimal avalanche danger. Complex cloud cover and clearing throughout the day. It was a good day to get info further north and east of the typical Hwy 20 corridor, where the snowpack is relatively shallower.
No signs of instabilityWeather
- Cloud Cover
- overcast
- Wind Loading
- none
- Rain Elevation
- NA
- Recent Snowfall
- 0
- Snow Avail For Transport
- small smounts
Overcast till 12p throughout the zone. In the PM, mid-level valley fog was in place east of about Winthrop and moved up to Mazama. More clearing further west in the zone. At 6,100ft, winds were calm. We saw no current or previous wind transport. Visibility was excellent in the afternoon. We had views of high peaks west of Rainy Pass, the Sawtooths, and into the Pasayten Wilderness.
Snowpack
Most snow surfaces were dry. We found significant near-surface facets (up to 2mm) and surface hoar (up to 6mm) in the top 3cm of shaded slopes. The sun softened steep SSW-SSE slopes above 5,000ft. Low-elevation solar slopes stayed frozen due to cloud cover.
Snowpack heights
3600ft: 60cm, 5,400ft: 145cm, 6,100ft: 155cm
Low elevations still hold a shallow snowpack. At middle and upper elevations, the snowpack is relatively strong and uniform for this location and time of year. While there are no older weak layers that are an immediate concern for human triggering, there are a couple of lingering interfaces in the upper snowpack, as well as, a crust-facet layer in the middle of the snowpack. I did not find buried surface hoar in the upper snowpack, however, I did find some recently buried surface facets.
We dug a profile at 6,099ft on a ENE aspect. HS 155cm. See attached graph. Notably, this snowpack was void of many prevalent crusts found further west. There was only one thin, prominent crust in the mid-pack (mid-Dec?). Two other, very faint crusts were in the lower and upper snowpack, respectively. The two most notable interfaces were:
@ 130cm on 0.5mm facets (FCsf): sudden results in small column tests, no propagation in large columns. CTM(SP), ECTN22
@ 70cm on 1.0mm facets (FCxr) with an overlying ice layer: sudden results in small column tests. DTH(SC)
Avalanche
No avalanches were observed. We saw a few small rollerballs and tree bombs on steep, sunny slopes that were at least 2 days old. We also saw many tracks and evidence of significant snowmobile slope testing from the past week with no resulting avalanches.