Support the forecast! Support the forecast!

Give to Friends of the Chugach National Forest Avalanche Info Center.

Observation: Turnagain

Location: Magnum

Date:
Observer:
Route & General Observations

Ascended Bertha Creek drainage to lower meadows below Corn Biscuit to dig on a lower North aspect (1700′.) We broke trail between 1200′ to 1700′ and didn’t experience any collapsing in the lower elevations. Skinned across Bertha Cr to PMS bowl on Magnum SW aspect and followed pre-exiting skin track to 2700′. NE winds started blowing snow in valley bottoms around 12pm. Cracking was observed in top 1″ of surface snow.

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?No
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?Yes
Observer Comments

Blowing snow and isolated cracking in surface snow.

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

Temperatures were in the high 20F's near the road and cooler as we ascended. Sustained 10-15mph NE winds at 2700' by 1:30pm. Snowing 1cm/hour.

Snow surface

Total of 3" of new snow covered the skin track on top of 15-24" of older settled snow.

Snowpack

See pit diagrams for details.

At 1700' on a N aspect the HS=107cm, slope was 39*. We did not find any buried surface hoar in this particular location. There was 18" of settled new snow from last week sitting on a variable wind crust. On one side of the pit the old wind slab was 3" thick and on the other side it wasn't there at all.

At 2700' on a SW aspect the HS= 141cm, slope was 38*. We found a wind slab layer with small facets that was only reactive in Compression tests (CT7.) There was a uniform layer (10cm thick) of Fist hard facets (3mm) sitting above a melt/freeze crust on the ground. It only required moderate force to to fail in compression tests (CT12) but didn't not propagate with an Extended Column test. However once the weak layer was initiated in a propagation saw test it failed easily to the end with some energy. PST35/100 End.

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.