Observation: Public
Observation Details
Name:
Zack WentzObservation Date:
December 24, 2020Submitted:
December 25, 2020Zone or Region:
West NorthActivity:
Skiing/SnowboardingLocation:
Table Mountain CircumnavigationTriggered Avalanches
Did you trigger any avalanches?
YesWas it intentional?
YesAvalanche Type:
Hard SlabSize:
Size 1: Relatively harmless to peopleElevation:
5200Aspect:
NWComments:
Location: Small wind-lip immediately below the saddle of Table Mountain and Video Peak. Avalanche Depth: 25cms down on the 12/21 interface. 1F+ hard slab sits atop this interface. Avalanche Width: 50 feet Avalanche Length: 30 feet Slope Angle & Characteristics: 35 degree concave slope This was the first of many touchy wind slabs triggered by ski cutting throughout the day. I tested multiple slope shapes (convex and concave test slopes), and any wind-loaded feature above 35 degrees reported some results from ski cutting. Most of the results produced arrested quickly, but fractured very easily and propagated across the whole feature.Observed Avalanches
Did you observe any avalanches?
YesAvalanche Type:
Hard SlabSize:
Size 2: Could bury, injure, or kill a personElevation:
5400Aspect:
NWComments:
Numerous D1-D2 wind slabs on NW facing features above treelineSigns of Unstable Snow
Observations
Avalanche Obs: See above
Snowpack Obs: Numerous hand shears reported easy, sudden results down initially on the most recent wind interface (down 10cms), and then digging past the most recent wind scouring, saw easy, sudden results on the 12/21 MFcr. Dug a quick test profile on a 35 degree test slope above treeline (elevation approx. 5300 ft). We got an ECTP1 down 25cms on the 12/21 MRcr interface. We originally thought the wind slab was confined to the upper 10cms of the snowpack, but these test results and numerous avalanches happening with ski cutting on this layer, demonstrated that these wind slabs are extremely touchy and fracturing deep (25cms down).
Weather Obs: Clear & cold. Mod.-Strong ridgetop winds from the East all day. Moderate blowing snow; loading W-NW aspects.
-Zack Wentz
Advanced Observations
Observed Avalanche Problem #1:
Wind SlabComments:
Location: Widespread above treeline, with the most sensitivity on W-NW facing slopes.Likelihood of Triggering: Very likely (extremely sensitive)
Layer Depth & date: 25cms down on 12/21 MFcr interface