| Trigger | Skier | Remote Trigger | 0 |
| Avalanche Type | Soft Slab | Aspect | North Northwest |
| Elevation | 3900ft | Slope Angle | 30deg |
| Crown Depth | 12in | Width | 150ft |
| Vertical Run | 150ft |
Avalanche: Hatcher Pass
Location: Hatcher Pass/Summit Lake
Toured back the Hatcher Pass road to the pass. Between 1pm and 4pm, light snow, temps high 20s, increasing cloud cover. Low snow, however, decent coverage all thing considered.
Avalanche Details
Avalanche triggered by unknown snowboarder. Soft slab (new snow from December 2nd) which stepped down into older layer, but generally not to ground. Variable crown depth between ~6 inches and ~36 inches, with average depth around a foot. Trigger point looked to be a wind loaded spot, where snowpack transitioned from thing to fairly deep. Did not attempt crown profile, rather we opted to dig a pit nearby.
Obvious signs of instability
| Recent Avalanches? | Yes |
| Collapsing (Whumphing)? | Yes |
| Cracking (Shooting cracks)? | Yes |
Observer Comments
Recent rider triggered avalanche (reported here), large, propagating collapse, shooting cracks
Weather
Between 1pm and 4pm, light snow, temps high 20s, increasing cloud cover.
Snow surface
New snow since the day before (December 1, 2018)--slightly wind stiffened
Snowpack
Poor structure found everywhere we looked. The location of our snowpit was the only place we found a generally right-side-up snowpack.
Multiple ski pole probes and hand pits showed a new snow soft slab, overlaying melt/freeze crust, following facets, another melt/freeze crust, and basal facets.
Single snowpit at Hatcher Pass/Summit Lake area: 3800 ft, west aspect, slope ~0, depth of snow 61cm.
CT 1 18cm from surface, new snow interface; CT 18 40cm from surface, melt freeze crust above basal layer of pencil hard snow; ECTP 3 18cm from surface, new snow interface; ECTN 21 40cm from surface, melt freeze crust above basal layer of pencil hard snow.
Snowpit at Hatcher Pass/Summit Lake area ~ 200 meters from reported avalanche