Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
February 5, 2022
Submitted:
February 5, 2022
Observer:
NWAC Forecaster - Dallas Glass
Zone or Region:
West South
Location:
Cortright Butte/ Hogback Mt (All aspects near and below treeline.)

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced

Media/Attachments

Human triggered rollerballs on a steep SW aspect at 6200' around 2pm.
Two to three inches of wet surface snow failed on this steep slope as I traveled across it around 2pm. SW, 6200'
A very strong crust with a noticable ice layer caps the Late Jan Facet-Crust sandwich in the White Pass backcountry.
A snow profile at 5900', N near Miriam Lake. You can very clearly see the 1/30 interface and the Late January Facet-Crust sandwich. However, this layer did not fail in any snowpack tests.
This ridgeline normally has cornices, but they are all erroded back. Wind was actually stripping the slopes on the left and depositing snow to the right (west facing). This is an unusual loading pattern for this area.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Sunny
Temperature:
38°F
Wind:
Light , NE
New/Recent Snowfall:
Trace

A really nice day in the mountains After some early morning mist, clouds dropped and dissipated leaving mostly sunny skies. Temperatures warmed noticeably around 1pm, but light and cool NE winds kept upper elevation areas feeling cold.

No new avalanches were seen.

Snowpack Observations

Below Treeline: I was surprised at how much wind effect there was below treeline. Some SW-W slopes were scoured back down to rock. Evidence of wind transported snow was easy to find and even extend into forested areas. However, we did not see any wind slabs as we traveled.
Rollerballs were prevalent below treeline around 2pm, however, no loose wet avalanches were observed.

Near Treeline:
Wind: Nearly all snow surfaces in the near treeline band are wind affected. This created a highly variable surface. Winds were typically loading SE-S-SW aspects. The most consistent wind slabs I found were on SE slopes. This is an unusual loading pattern. Normal cornice lines were eroded back. Normally wind-loaded slopes were stripped bare. Wind-affected snow extended well off the ridgelines all the way to the bottom of the terrain features.
Loose Wet: Trees started dripping water around 1pm as the temperatures noticeably warmed. I was able to trigger small rollerballs on a SW asepct at 6200' around 2pm, but these pinwheels quickly fell apart as they descended. A cool NE breeze was keeping all but the most wind sheltered slopes cold and dry. A thin layer of moist surface snow was found on S-SW slope as I exited the field.
Late-January Facet/Crust: The 1/30 interface was down 10-18" (25-45cm). On sunny slopes the 1/30 is a very thick and strong melt-freeze crust with the snow well bonded to it. On shaded slopes, the upper crust in the sandwich was 1-2" thick and contained a very strong layer of ice. The layer of facets was thinner than other areas I've seen it, only 1" thick (2-3cm, FC 1-1.5mm). No snowpack tests failed on this layer today.

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