| Trigger | Natural | Remote Trigger | 0 |
| Avalanche Type | 0 | Aspect | North Northwest |
| Elevation | 2300ft | Slope Angle | 37deg |
| Crown Depth | 2ft | Width | 350ft |
| Vertical Run | 400ft |
Avalanche: Turnagain
Location: Main Bowl, Seattle Ridge
APU Snow Science class traveled to Seattle Ridge to look at Main Bowl slide from yesterday.
Avalanche Details
We took a good look at yesterday's slide in Mainbowl. HS - N - D3 - O.
We dug in at the left flank of the avalanche. The weak layer was 10 cm of fist hard facets 2.5 ft (80 cm) down. Bed surface was pencil hard melt freeze crust. Slab consisted of two parts, pencil hard rounds just above the facets, but the top half was softer. The debris was mix of up to refrigerator size hard blocks but also softer, smaller chunks.
Obvious signs of instability
| Recent Avalanches? | No |
| Collapsing (Whumphing)? | Yes |
| Cracking (Shooting cracks)? | No |
Observer Comments
Several whoomphs observed while traveling along Seattle Ridge between common uptrack and Main Bowl. One was very loud and propagated widely in a flat area, quick pit revealed 20 cm slab on top of 5 cm of advanced facets on bullet proof crust.
Weather
Bluebird sunburn kind of day at the pass. Temps 30s to 40s. No new snow. Calm in the morning, but wind picked up in the afternoon..
Snow surface
Morning travel easy skinning on supportable melt freeze. This corned up nicely for afternoon ski back to the van.
Time bring skin wax for tours with more moist surface snow.
Northerly snow surface stayed cooler and offered nice ski quality (in mellow terrain!).
Snowpack
We dug at several locations ENE and WNW aspects around Main Bowl. The weak layer of facets was consistently found at 80-120cm depths. This layer was stubborn and we did not get any test results (6 x ECTX & 3 PST no result), except one DT14@facet layer near the right flank of the slide.
View of debris from left flank. Larger hard blocks were size of a refrigerator.
Weak layer 1-2 mm facets, we did not see buried surface hoar in grain samples.
Photo of layers found at left flank of slide.
View of crown from left flank. Slab depth was estimated to be quite consistent at 2.5 ft, angle was estimated to vary between 35-40 degrees.