Observation: NWAC Observer
Basic Information
Observation Details
Observation Date:
February 21, 2023Submitted:
February 21, 2023Observer:
NWAC Observer - Keeley RideoutZone or Region:
West CentralLocation:
North side of Mountain Loop Hwy (1000-3820ft, All Aspects )Signs of Unstable Snow
Recent Avalanches?
None ObservedCracking?
None ExperiencedCollapsing?
None ExperiencedMedia/Attachments
Advanced Information
Weather Summary
Cloud Cover:
OvercastTemperature:
26°FWind:
Light , WNew/Recent Snowfall:
HN: 32cmSteady cold snowfall ~1cm/hr with light winds from 10am -2pm that subsided after 2pm. No blowing snow, but wind drifts and ample loading in open pockets below treeline. Evidence of strong winds out the west plastered snow to the east side of trees during the recent storm, even in densely forested areas (see pictures).
We may have seen avalanches at upper elevations in surrounding terrain, but we were totally socked in and saw no avalanche activity in our immediate surroundings other than some rollerballs of varying sizes present on cutbanks.
Snowpack Observations
Snowline started ~1500ft. We dug an east facing pit at 3810ft. Total snow depth was 210cm. Cold, low density powder comprised the top 32cm which sat atop a 2cm crust. Immediately beneath that crust we found a thin layer needle snow grains creating a weak layer. Packed powder made the rest of the snowpack until another distinct crust 85cm from snow surface. This layer had large grains that crumbled when we poked them, but there was more water in the snowpack both above and below this crust so, despite being crumbly with direct shear force, a column test did not produce any results on this layer and it seemed really cohesive. The column test did however produce a resistant planar fracture at the needle layer around 25cm down. We also attempted to ski-cut some steep, wind loaded cut banks and were unable to get any results despite really thoroughly jumping on them.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wind Slab
|
|
Unknown | |||
| None Specified |
|
Lots of evidence of wind loading even below treeline makes wind slab a primary concern. Rime on trees within the forest as well as windrifted pockets in open patches were present at elevations above 1150ft. We experienced no cracking when skiing through wind loaded spots.