Avalanche: Hatcher Pass

Location: Bomber Traverse, Bomber Pass, Lynx Peak, Snowbird Glacier

Date:
Observer:
Route & General Observations

We completed the Bomber Traverse from 3/31-4/2/18, starting from Mint Valley TH & ending at the Snowbird Glacier out to Reed Lakes. During our travels we did not see any significant/current signs of instability or any red flags aside from a recent avalanche on a south-facing slope on the Snowbird Glacier.

Avalanche Details
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Trigger NaturalRemote Trigger0
Avalanche Type UnknownAspect South
Elevation 2500ftSlope Angleunknown
Crown DepthunknownWidthunknown
Vertical Rununknown  
Avalanche Details

Recent avalanche that looked to have released within the last 24-48 hours on a rocky, south-facing slope in the Snowbird Glacier area (visible from Snowbird Hut windows). The crown was clearly visible and ran maybe 300ft across a rocky slope. Absence of tracks indicated that it was a natural slide, possibly from a combination of the warming rock temperature and increasing winds on Sunday or Monday (4/1-4/2). What was most concerning was the large volume of skier and snow-machiner tracks on/beneath similar slopes in the same area.

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)?No
Cracking (Shooting cracks)?No
Observer Comments

From Mint Valley to Bomber Glacier the only concerning indications of avalanche potential were small to large (bowling bowl-sized) roller balls coming off of southerly aspects that were increasing in size with the winds that picked up on 4/1 around 4pm. Images uploaded are of flagging on Lynx Peak around 4pm on Sunday and old avalanche debris from a cornice break on the N side of Bomber Pass. On Monday 4/2, we observed the avalanche crown & debris on the Snowbird Glacier avalanche described above.

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

25-35 degrees, clear skies, no wind until the evening of 4/1. Winds picked up to maybe 15-20 mph (?) Sunday afternoon and evening and persisted into Monday.

Snow surface

Mint Valley: sun crust and pockets of settle powder. Backdoor Gap: suncrust becoming increasing wet/melting by 11am. Penny Royale Glacier: settled powder. Bomber Glacier & Bomber Pass: settled powder, areas of wind crust & suncrust. Snowbird Glacier: settled powder and suncrust. Glacier Creek: suncrust. Reed Lakes valley area: lots of suncrust/melt-freeze crust, worst snow surface conditions of the trip. Surface conditions from Backdoor Gap to Bomber Pass, Bomber Glacier, & Bomber Hut were by far the best. We did not spend any time skiing in Snowbird Glacier area but other parties reported lots of settled and protected powder.

Snowpack

Our party did not dig a pit or conduct a stability test. One party dug a pit on a NW aspect on a 30 degree slope in the Bomber Glacier area at around 3000ft and reported minor fracturing w/out propagation below the new snow (5-6") on top of a stout wind crust during an extended column test.

Photos & Video
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