|Location:||Hatch Peak, Sunnyside of Hatch|
Route & General Observations
Fishhook Lot to Hatch Peak. Skied Sunnyside of Hatch, skinned back up, skied SE off Hatch Common. Triggered REMOTE avalanche.
Many areas at mid elevation lack a significant slab. The snowpack is generally old, shallow and almost completely composed of weak, soft, faceted snow. Rocks, grasses, and bushes are protruding through the shallow snowpack.
Upper elevations are dramatically different with a much deeper snowpack on west to north aspects, from wind-loading from the predominant wind direction. East to South aspects have hard slabs sitting on weak, shallow snow on wind scoured aspects, generally, South to East. These hard slabs were formed earlier in the season by northerly winds.
Winds have generally been light by Hatcher Pass standards, with many areas with undisturbed boot top, re-crystallized, soft snow.
|Trigger||Skier||Avalanche Type||Hard Slab||Aspect||Southeast|
|Elevation||4300ft||Slope Angle||37deg||Crown Depth||24in|
Hatch Peak, SE face, remotely triggered, third skier, from 350´away on a connected slope.
Debris depth estimated in specific terrain trap locations up to 10+ feet deep
No recent avalanches, No whumphing, No cracking.
Poor structure in the snowpack. 4-5 lemons.
1.5cm new snow overnight
11:45am, -5.5C, calm wind, sky Few @ 3230'
2:30pm, ESE winds gusting moderate @ 4800'
Clouds building through day from the South, overcast by 4:00pm
0.3-0.5 surface hoar on top of 1.5 cm new snow overnight.
The structure of the snowpack is the most significant observational clue to instability.
Buried surface hoar is suspected as the culprit in today's avalanche and has been found at this elevation and in the area. It is very likely that this avalanche was triggered on BSH, which then stepped down to the MF crust and the ground.
Mid elevations on east ridge of Hatch, ENE, 3500', 30 deg slope, HS 50-70cm, showing strong strength, poor structure, low energy (propagation) on F/4F/1F slab component over facets on a MF crust (ECTN23, CT25PC, PST 93/100END). Basal facets not failing in ECT or CT, but did fail in PST 48/100, 60/100END.
E, 3240', 30 deg slope, HS 75, ECTX, CT26SC down 57cm above MF crust, CT16SC down 59cm below MF crust. Moderate to strong strength, poor structure, variable energy (propagation).