Avalanche: Hatcher Pass

Location: Hatch Peak

Date:

February 4, 2017 2:30pm

Observer:

J Haffener & S Galoob

Route & General Observations

Skinned up $1000 dollar run, booted up N Ridge of Hatch Peak (above Summit Lake), enjoyed the warm sunshine, booted back down the ridge after digging pits, and skied Bennet’s Ridge to Hatcher Pass road and down.

Avalanche Details

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Trigger	Natural	Remote Trigger	0
Avalanche Type	Wet Loose Snow	Aspect	South
Elevation	4200ft	Slope Angle	unknown
Crown Depth	unknown	Width	50ft
Vertical Run	200ft

Avalanche Details

Several loose wet avalanches observed on the South face of Skyscraper that likely occurred on 2/3 during the big warm up. Most originated near rocks and ran on the depth hoar. The largest one ripped out to ground. Also lots of roller balls observed that previously released from rocks on this face.

Red Flags

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Obvious signs of instability

Recent Avalanches?	Yes
Collapsing (Whumphing)?	No
Cracking (Shooting cracks)?	No

Observer Comments

Wet loose avalanches observed that looked recent from warm up yesterday. No whumphing or shooting cracks. We jumped on a lot of test slopes.

Weather & Snow Characteristics

Please provide details to help us determine the weather and snowpack during the time this observation took place.

Weather

So warm and wonderful in the sunshine! Calm to light winds.

Snow surface

~4 inches of settled powder in middle sheltered elevations near the road that had not been affected by wind. Most mid elevations had breakable wind slabs ranging in depth from 1-6 inches. "Orange peel" texturing of the snow was found on the flats headed to $1000 dollar run ridge. $1000 dollar run ridge had breakable 1F to pencil hard wind slabs, impenetrable knife hard crusts, areas stripped to rock, and areas stripped to advanced depth hoar 3-4 mm in size. The N Ridge of Hatch Peak was stripped to rock and the summer trail was mostly visible. Off the ridge the snow was mostly chalky thick boot top to barely penetrable wind slabs. On the Southern aspects of Hatch the snow was moist, icy, and slick.

Snowpack

Pole probing revealed light settled powder (in mid elevations closer to the road) over wind slabs varying in thickness over facets to well developed depth hoar. Upper leeward elevations were loaded with very thick wind slabs sitting over facets. We found several melt freeze crusts between wind slabs and depth hoar on the sunny side of Hatch and found one melt freeze layer between the depth hoar and wind slabs in April Bowl on a due North loaded aspect. Formal pit results below:

Pit 1: Hatch Peak - Above Summit Lake, 4525 ft, W, 30 degrees, HS = 95 cm, boot pen = 10 cm.
Easy hand pit failure and ECTN 22 PC at the 1F / 4F interface 17 cm down.
CT 19 SP and ECTN 21 PC 27 cm down on snow interface between 4F 1 mm facets and 1F 2mm facets
95
1F wind slab
78
4F 1mm facets
68
1 F going to P, 2-3mm facets
20
1F 3-4 mm depth hoar
G

Pit 2: Hatch Peak - April Bowl, NE, 28 degrees, 4,700 ft, HS = 120 cm.
CT36 SC (outside test parameters - both arms from shoulder), ECTX, ECTP36 SP (outside test parameters - both arms from shoulder), PST 30/100 END - all down 80 cm wind slab over 2mm facets over a 1cm faceting ice crust.
120
P+ wind slab
60
1F facets
40
F facets
38
K faceting ice crust
37
1F facets
20
1F depth hoar
G

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