Support the forecast! Support the forecast!

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

Observation: Turnagain

Location: Magnum - PMS Bowl

Date:
Observer:
Route & General Observations

Field Observations
Feb.5, 2015

Route
Magnum to 3550′

Weather
Temps: 8F at valley floor and 20’sF near 3500′
Wind: Light (5-10mph)
Sky: Sunny
Precip: None

Obvious Signs Of Instability
Recent Avalanches- NO
Shooting Cracks- NO
Collapsing – NO

Glide Avalanches/Cracks- No new activity observed, but the photo below tracks the movement of a glide
on Tincan over a 20 day period.

Surface Obs –
1000′: 2-3″of low density snow on ground
2500′: 2-3″ of low density snow on stout Melt/freeze crust below
3500′: 2-4″ of low density faceting snow old snow interface

*Found a 1-2cm sun crust only on very steep Southern features, but it was not found on the SW aspect of
Magnum’s PMS bowl. Skiing quality is still really good!

Snow Below the Surface:

Pit at 3200′ SW aspect, HS=242cm, 32*slope, ECTN23, 40cm below the surface. Failed under a 1cm
melt/freeze crust. No propagation potential was observed in this pit.

Pit at 3500′ SSW aspect, HS≈95cm, 34*slope, ECTP24, ECTP26, failure was 45cm below the surface on a
faceting layer sandwiched between an ice crust above and pencil hard old snow layer below. The facets
were small (1mm) and showed some slight signs of striation. See pit profile for details.

The pit at 3500′ shows some evidence that the prolonged cold temperatures have been forming facets
within the first 15 inches of the surface snow. Above 3200′ the multiple crust layers disappear and become
a single thin ice crust at 3500′ on Magnum. Note the similar depth of the thickest crust at 3200′ and single
crust at 3500′. Both are in the 40-45cm range.
Right now these layers aren’t much of a concern, but they will be important to pay attention to if we get a
significant loading event.

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.