| Trigger | Skier | Remote Trigger | 0 |
| Avalanche Type | Soft Slab | Aspect | Unknown |
| Elevation | 2400ft | Slope Angle | unknown |
| Crown Depth | 18in | Width | unknown |
| Vertical Run | unknown |
Avalanche: Turnagain
Location: Tincan Trees
Tour up to treeline to assess the new snow character and how it is bonding with the old snow surface. Bonding was poor and several human triggered avalanches occurred on the small terrain features of the Tincan Trees.
Avalanche Details
Several human triggered soft slab and wind slab avalanches on the Tincan rolls near and below treeline today. Appeared all avalanches were failing on buried surface hoar. Most were small due to the small terrain features. Most were around 12" thick, one wind slab was up to 3' thick at the crown. Also, one larger slab was noted under Jerome's Dome and was 1-2' thick, 150-200' wide and running 150-200 long. See photos.
There was NO visibility for any observations or travel above treeline.
Obvious signs of instability
| Recent Avalanches? | Yes |
| Collapsing (Whumphing)? | Yes |
| Cracking (Shooting cracks)? | Yes |
Observer Comments
All signs of instability present today - collapsing, cracking and recent avalanches.
Weather
Moderate snowfall (1/2 inch per hour) and gusty erratic winds (moderate to strong) at treeline. Very poor visibility. Storm day.
Snow surface
Low density powder, in the 5% range out of the wind. 10" at the parking lot and 12" at treeline ~2,400'.
Near treeline winds were forming soft wind slabs.
*Drove to Sunburst after tour, only 4" new snow and Johnson Pass, 3" new in parking lots. North end of Turnagain Pass clearly favored by this storm.
Snowpack
New snow was collapsing and sheering easily on the surface hoar it fell on in many locations. However, good bonding was also seen in some areas (likely due to skier traffic yesterday during the beginning of storm.
See pit photo for structure. Essentially, new snow fell over buried surface hoar which sits over 1-3" of near surface facets which sits on a harder layer of ice/wind packed snow/wind crust. The most reactive layer at this point looks to be the buried surface hoar. The culprit for the many human triggered avalanches today.
The thin grey line - tell tell sign of buried surface hoar, not what we want to see in our snowpack
Human triggered wind slab - from below - on buried surface hoar near treeline where the winds were loading slopes
Small soft slab avalanche triggered on a small roll while ascending
Shooting crack along treeline on Tincan
Many many rolls near treeline exposed to the wind were triggered today by skiers/snowboarders
Excavation of a crack in the slab that stops at the buried surface hoar - you can see the downhill portion of the buried surface hoar has collapsed into itself and is thinner than the uphill portion
Finally some new snow for the New Year! Tincan uptrack filling in slowly