Avalanche: Hatcher Pass

Location: Microdot and Road Observations

Date:

December 27, 2021 8:19pm

Observer:

Jed Workman Forecaster

Route & General Observations

Toured from IM parking lot to a sub-peak of Microdot. Breakable crust from 3000′-3800′. The crust became more supportable the higher up I traveled, completely supportable from 3800′-4200′.
I traveled the road system carefully inspecting for evidence of avalanches and dug a few holes at various elevations to inspect moisture saturation of the snowpack. See pictures.

Avalanche Details

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Trigger	Natural	Remote Trigger	Unknown
Avalanche Type	Soft Slab	Aspect	South
Elevation	3800ft	Slope Angle	unknown
Crown Depth	unknown	Width	unknown
Vertical Run	unknown

Avalanche Details

Saw this avalanche which failed near the ground during or just after the storm, 12/26-27. D2 in size. The current theory is that a rapid load of rain falling on snow naturally triggered this avalanche and several others. In today's tour the snowpack was dry under two rain crusts near the surface at this elevation.

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

Red flags observed were limited to recent avalanches failing in old faceted snow near the ground during or just after the storm.
These were observed at the upper elevations running into the mid elevation band. D1.5-2 in size.
No cracking, No collapsing, No avalanches triggered on my tour.
A large group of people reported whumphing in several locations and ECTP Moderate results on buried facets, our PWL of concern.

Weather & Snow Characteristics

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

Weather

11am to 2pm
32F at 3000'
26F at 4500'
Sky overcast over Hatcher Pass with some light coming through Broken skies to the South
Winds calm

Snow surface

1700' and below, no crust, some standing water on roadway
2500' 1/8-1/4" Crust breakable, frozen roadway 1/2" of ice on road, about 1" of ice in parking lots from here up to top of road- most hazardous part of the day = walking on ice. I saw at least one person fall hard on ice while walking with snowboard in hand.
3000'-3800' 1/2" crust breakable, double crust sandwich with dry snow meat
3800'-4200' 3/4-1" crust completely supportable, very loud skiing, wish I brought earplugs

Snowpack

1700'-2500' Entire snowpack is moist and weak, mostly F hard
2500-3000' Transition to dryer snow under crusts
3000'-4200' dry snow under crusts gaining thickness with elevation, likely supportable crust from 4200'-5000'

Photos & Video

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