Avalanche: Hatcher Pass

Location: MicroDot South Face; Swimmin' Tims

Date:
Observer:
Andrew Dennis
Route & General Observations

JK’s birthday tour. Started at IM lot and took standard route to MicroDot sub ridge above Nosebleed and Swimmin’ Tims. We did two runs on Swimmin’ Tims and exited via MicroDot Dot. Good creamy pow skiing. Poor visibility.

Avalanche Details
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Trigger SkierRemote Trigger Yes
Avalanche Type Soft SlabAspect South
Elevation 4400ftSlope Angle 38deg
Crown Depth 20inWidth 150ft
Vertical Run 700ft  
Avalanche Details

On our group's second run on Swimmin' Tims we started from slightly higher up on the ridge. The first skier entered the run skiers left of previous tracks and remotely triggered a persistent slab avalanche that initiated about 20 feet down slope. The avalanche ran to valley floor. No one caught or carried. Ski tracks and "safe transition zone" from previous run were not entrained. Probed debris depth was 145cm although we might have not found the deepest spot.

See above details. See attached pictures.

20220123~0130: SS-ASur-R3-D1.5-O

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Obvious signs of instability
Recent Avalanches?Yes
Collapsing (Whumphing)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

There was a recent size D1 wind slab avalanche on a slope that had similar slope angle, aspect, and elevation to the slope in which the avalanche occurred. We experienced one or two "whumps" and some localized cracking in wind load terrain on the tour up.

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

HPAC Weather Page: https://hpavalanche.org/weather/

Marmot Weather Station: http://www.cnfaic.org/wx/wx_site.php?site=marmot

See also: Independence Mine Snowtel

There was recent warm storm that added 0.8 SWE to the snowpack. This storm had associated S/SE winds from 10-35mph.

During the tour temperatures were pleasantly warm with unpleasantly flat light. SE winds were transporting snow off the high peaks throughout the day; we were mostly protected from wind in our location.

Snow surface

Creamy Pow! We did not feel the Christmas Crusts when skiing. On the approach there were areas scoured down to the Christmas Crusts.

Snowpack

Informal hand shears and ski cuts revealed relatively shallow wind slab with weak to moderate adhesion strength to the crusts below. No formal pits were performed today. Known widespread persistent slab problem with propogating results in recent test pits.

Photos & Video
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Wind slab steps down to persistent slab  

Remote trigger persistent slab  

cracking and flagging