Wind Slab Avalanches Long Canyon

Location Name: 
Wind Slab Avalanches Long Canyon
Region: 
Long Canyon Area
Date and time of observation: 
Tue, 02/25/2020 - 12:51


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path

Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

Moderate NW winds continue to transport snow on Tuesday at ridgelines.  Went to Long Canyon to check out what the westerly winds have been doing on East aspects near and above treeline.  I remotely triggered an avalanche that was failing on near surface facets below the crust that formed from the last round of high pressure that formed before this last round of snow (See Video).  We were getting loud audible collapses during the tour above 11,500' where more snow had fallen.  We triggered several avalanches today on East aspects.  While traveling on ridgelines or cornices are really starting to grow with the wet snow and winds.  We had cornices breaking further back than expected and triggering avalanches in the slopes beneath.   

Photo 1: two avalanches that we remotely triggered today from the ridgeline

Photo 2:  Cornice that we got to fail with the subsequent avalanche below

Photo 3: Cracking further back on the cornice from the ridgeline where we got the cornice to fail

Photo 4: Cornices are getting bigger on the Long Canyon ridgeline with the west slopes scoured and the East slopes loaded with the recent snow

Photo 5: Looking at the crown with the near surface facets below the crust being the weak layer to fail

Photo 6: 100' below where we remotely triggered an avalanche.  New snow on top of persistent weak layers

Snowpack photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Air temperature trend: 
Warming
Wind Direction: 
Northwest
More detailed information about the weather: 

A mix of sun and clouds in the morning with increased clouds and light snow flurries in the afternoon.  Winds were moderate on ridgelines out of the NW with snow being transported onto leeward aspects.