Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
March 12, 2022
Submitted:
March 12, 2022
Observer:
NWAC Forecaster - Matt Primomo
Zone or Region:
Stevens Pass
Location:
Jim Hill (NW-E 2,800-6,400ft)

Signs of Unstable Snow

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

Media/Attachments

N at 4,800ft showing weak snow above the crust, buried by a few cm's of recent snow.
NE at 5,200ft showing the very weak, faceted layer above the crust, buried by a few cm's of recent snow.
About 20cm's over the early March crust in some places. N at 6,000ft.
Surface textures: Soft, faceted snow lightly etched by the wind over rain crust and runnells. N at 5,900ft.
Surface textures: soft, faceted snow, wind etched. NW at 6,000ft
Large faceted grains just above the crust from early March. These were from where the crust was within a few CM's of the surface. N at 6,000ft.
I found some sharp needles just under a cm or so of snow, just below ridgecrest- N at 6,350ft.
I found some sharp needles just under a cm or so of snow, just below ridgecrest- N at 6,350ft.
Debris at about 5,800ft below Jim Hill.
Looking down the main slide path on Jim Hill with very large debris from the late Feb/early March cycle.
E and SE facing slopes with rain runnells still visible.
ESE facing slope at 6,400ft on Jim Hill holding what looks like some dry snow.
Wind affected NW facing terrain in the Chiwaukum Range.
Open creeks pose a hazard in the lower track of Jim Hill.

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Wind:
Light , SW

Nice day with some scattered clouds. Temps warmed quickly by late AM.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Feb 28, 2022
() 		Jim Hill main bowl
N 6400ft 		D3
R4 		HS-Hard Slab O-Old Snow N-Natural
D3 avalanche in Jim Hill bowl, likely from Feb 28th.
D3 avalanche in Jim Hill bowl, likely from Feb 28th.
Report
Jim Hill main bowl

Snowpack Observations

I found melt forms and thick crust below about 4,500ft, which softened up to nice corn by noon.

Above 4,500ft I began finding a layered structure with faceted grains above the early March crust. From 4,500ft to 5,000ft a thin temperature crust from the previous day existed above 1mm faceted grains, all over the stout crust.

From 5,000ft to 6,000ft I found the most consistent weak structure, with about 8cm of snow over the early March crust. The weakest, and largest faceted grains (Fist hardness and 1.5-2mm facets) were always just above the stout early March crust, capped with some new snow from the 8th. This snow had begun to facet out as well, but the grains were generally smaller and the layer slightly harder. Some profiles showed a few layers of stiffer wind skin resting over the weaker snow from the 8th. I could get columns to slide off the early March crust fairly easily with tilt tests, though the blocks were often breaking apart with crumbly snow.

Above 6,000ft I started finding more variable snow surface conditions with lots of interesting textures from wind etching. Some areas held small pockets of stiff, older windslab. Some of these rested on the same weak faceted grains just above the crust. Other areas had been scoured down to what was previously moist snow above the crust. This snow had become weaker with large-grained (2mm) striated facets. About 50ft below a ridgeline I found buried needle-like surface hoar below about 1cm of more recent snow. The newer snow broke off easily.



WordPress Lightbox