Date of Observation: 02/01/2016
Name: Zach Guy and Ian Havlick
Aspect: North East, East, South East, South, South West
Elevation: Below treeline
Avalanches: See video. Widespread natural storm slab instability on all aspects, mostly shallow and D1 to D1.5, but a few failing deeper and/or running long and far up to D2 in size (like the slides onto Kebler Road from 7 Sisters, where debris piles were 6 feet deep on the road). SS-N-R1-D1/D2-S.
We remotely triggered and observed several similar naturals failing on either surface hoar layers or near surface facet layers at the storm interface up to 3 feet deep. SS-N/ASr-R2-D1.5/2-I. These were on E and NE aspects BTL.
Weather: Intense pulse of heavy snowfall (S5) ended around 9 a.m., with S-1 through the rest of the morning. Calm winds. Overcast skies.
Snowpack: About 30″ of storm snow, fist hard. Ski pen was mid thigh. Widespread muffled collapses and shooting cracks on low angled terrain, where the storm snow sits on a thin melt-freeze crust (2cm), or on facets or surface hoar. Steep south aspects hold a 10cm thick meltfreeze crust below the storm snow.
Remotely triggered slide, failed on surface hoar 3 feet deep. SS-ASr-R2-D2-I. E aspect BTL Interestingly, this path had also run a few hours earlier as a shallow storm slab. It ran again, much deeper down to the storm interface as we approached it.
Widespread shallow storm slabs ran naturally on all aspects, but put debris down along Kebler Pass Road in a number of places.
Widespread shallow storm slabs ran naturally on all aspects, but put debris down along Kebler Pass Road in a number of places.
Widespread shallow storm slabs ran naturally on all aspects, W, SW aspects BTL shown here
Crown of remotely triggered slide. Failed on surface hoar, 30″ deep. (1/29 interface)
Natural soft slab on 1/29 interface. East aspect below treeline. Either failed on facets or surface hoar. SS-N-R2-D1.5-I
Impressive propagation for a shallow storm slab