| Trigger | Natural | Remote Trigger | 0 |
| Avalanche Type | Soft Slab | Aspect | South Southwest |
| Elevation | 3900ft | Slope Angle | unknown |
| Crown Depth | unknown | Width | unknown |
| Vertical Run | unknown |
Avalanche: Hatcher Pass
Location:
Independence Mine to Microdot
Avalanche Details
This avalanche happened between 2-3 pm. Trigger is likely to be radiant heat.
Marmot Mountain, above the Archangel Trailhead, in a large bowl feature which runs into a steep creek/terrain trap.
Avalanches on similar aspects at lower elevations (approx 3000-3500'), may have sympathetically triggered the upper elevation avalanche.
Estimated SS-Ny-D1.5-I/O, 0.5-1 feet deep, 100-200 foot wide, ran about 600 feet. The crown was located mid-slope, rocks were visible in the bed surface giving some indication of depth of weak layer.
Lower elevations avalanches SS-N-D1.5-I 0.5-1 foot deep, ~200' wide just above the creek bottom. see pics
Obvious signs of instability
| Recent Avalanches? | Yes |
| Collapsing (Whumphing)? | Yes |
| Cracking (Shooting cracks)? | No |
Observer Comments
Natural avalanche today on Marmot Mountain, SSW, 3500', D1.5, mentioned above
Whumphing in areas where new snow had been previously drifted during 2/12-2/14 [Valentines Storm], was cohesive, sitting over surface hoar and 4F facets, up to 60 cm deep.
Weather
Clearing in afternoon. Microdot at 4136', -6.5C, winds 0-2.3 mph Variable and East
Snow surface
At 3000'-4500' = New snow 15 cm overnight, 60cm total from 2/12 to 2/15
South Southwest aspects begining to feel the heat of the sun and form micro-crust
Snowpack
60 cm new snow, F (top) to 1F (2/12 came in with wind) / 4F 2.0mm Facets and Surface Hoar
New snow/old snow reactive in pits (PST 25/100 at SW, 4100', 1F wind slab/2.0mm facets) and producing whumphing, shooting cracks up to 15' long failing on new/old.
Marmot Mountain, 2/15 Natural Avalanche, SSW, 3900' with Sympatrically triggered avalanches
Marmot Mt, SSW, 3500', Natural Avy
Microdot, SSW, 4200'
Sluffs in Nosehair Chutes, S, 4500'
Sluffs Skyscraper, E, ~3700'
Natural Sluffs and slabs, Eldorado, E, 4400'
Arkose ridgeline, Natural avalanche, NNW, 3900'