Observation: Hatcher Pass

Location: Powder Pimple and General obs

Date:
Observer:
Route & General Observations

Toured up to IM and Powder Pimple (of Hatch) to observe human behavior, avalanche activity, and assess cohesiveness of the snow. Conservative route choices dominated the day with one human triggered avalanche observed on lower Microdot. Numerous large loose dry sluffs from the storm could be seen in steep terrain. Slabs on all aspects, mostly from mid towards end of storm could been seen but mostly were obscured from winds on Friday. The sun warmed up the top 3-4″ of new snow on steep southerlies in the afternoon, forming more cohesive slabs, and sun crust should be expected today.

Avalanche Details
If this is an avalanche observation, click yes below and fill in the form as best as you can. If people were involved, please provide details.
Avalanche Details

Observed recent avalanches that occurred during the storm Friday. See photos
Observed one human triggered slab on lower Microdot on Saturday- see obs
Due to conservative decision making no other avalanches were observed or reported on Saturday.

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)?No
Observer Comments

Recent avalanche on lower Microdot on Saturday.
In the afternoon any steep slope with a southerly tilt had significant warming from the temps/sun. You could feel the slab becoming more cohesive. Hand shears were propagating with easy to moderate force and failing on graupel. I experienced whumping on a steep southerly test slope while ascending up towards the Powder Pimple.

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

IM reported 8" new snow from 3/23-24 which felt more like 10" in many locations.
Calm winds on Saturday.
Cool temps in the morning and parking lots, starting at 4degF at 8am and rising to 19degF by 6pm at 3550'.

Snow surface

Depending on the slope angle, firm bed surfaces can still be felt underfoot while skiing/riding.

Snowpack

We dug numerous hand pits and pole testing throughout the day. The goal was to assess how and where cohesive slabs existed and how they changed throughout the day. Many locations do not have a cohesive slab. As soon as the slope tilted slightly south in the afternoon on 35deg+ terrain you could feel surface warming and significant cohesion with the new top 3-4" of storm snow. Slabs were easy to moderate to propagate with hand shears, failing in the graupel on firm buried sun crusts. There is an equation here: If no slab exists and no firm buried crusts> this avalanche problem does not exist in that location. Where slabs exist , even "barely cohesive enough slabs" and they are sitting on a firm bed surface with graupel> triggering an avalanche will be possible.

Photos & Video
Please upload photos below. Maximum of 5 megabytes per image. Click here for help on resizing images. If you are having trouble uploading please email images separately to staff.