Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
February 3, 2022
Submitted:
February 3, 2022
Observer:
NWAC Forecaster - Josh Hirshberg
Zone or Region:
Stevens Pass
Location:
Lanham creek (3,000-5,600ft, NW-N-E)

Signs of Unstable Snow

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

Media/Attachments

Light rain moistened the snow surface and formed a crust on Feb 3rd. Lanham creek
Profile at 5,560ft, NE Lanham creek. The blue card is at the Jan 30th interface, down 48cm from the surface. Height of snow 260cm
A mid-storm interface from Jan 31st, down 35cm, fails in a tilt test. 5,560ft, NE, Lanham creek
Large 8-10mm melted surface hoar grains found at the Jan 30th interface. 3,350ft, NW, Lanham creek
Profile from NE, 5560ft, Lanham lake

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Wind:
Calm

Light rain/freezing rain as high as we traveled (5,600ft). Temperatures were above freezing @ 3,000ft at 8:30a and rose through the day. -1.0*C @ 5,560ft @ 12:30.

Small rollerballs below 4,000ft. No new avalanches observed.

Snowpack Observations

The two most notable observations were the unanticipated moist snow surfaces and the generally favorable bond at the Jan 30th interface on NW-NE throughout the terrain. Surfaces were wetted to varying degrees. Above 5,000ft, only a thin micro-zipper crust was present. Below 4,300ft, surfaces were wet and sticky and we were getting soaked from wet snow on the tree branches.

Targetting the January 30th interface on northerly aspects: Previously weak, faceted (or surface hoar) grains have seen considerable rounding/melting. In 4-5 quick profiles throughout the tour, we found test results, bond w overlying snow, hardness, grain type/size, all indicated that the Jan 30th interface is trending towards being less problematic for triggered avalanches within the areas observed.

Profiles:
5,560ft, NE, 31deg- See attached graph
HS 260cm
Layer of most concern ↓35cm- Jan 31st mid-storm interface 1.0mm DF. CTH (RP)x2, ECTN22
Jan 30th facets/melt forms ↓48cm- 1F- hardness, 0.5mm w lots of rounding/melting, capped w soft crust. No results in CTx2, PST 58/100 SF ↓48cm, ECTN28 ↓52cm

4,500ft, NE, open trees
Jan 30th FCxr ↓35cm, 4F+ hardness
moderate, resistant, rough hand shear results

4,140ft, Lanham Lake
Jan 30th FCxr ↓35-40cm

3,350ft, NW-NE, open meadows
Of 3 quick pits, 1 produced rounded/melted surface hoar (see photo), 8-10mm at the 1/30 interface
hand shears were moderate, resistant, rough on 1/30 SHxr ↓35cm

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wet Loose
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
Persistent Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: Jan 30th
Weak Layer(s): Jan 30, 2022 (FCsf)
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