Remote Triggered Hard Slab

Location Name: 
Snowpack Depths are Highly Variable
Region: 
Williams Lake Area
Date and time of observation: 
Fri, 01/24/2020 - 14:00


Red Flags: 
Recent avalanche activity

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

Went for a tour up the Williams Lake drainage. It was a beautiful day, and climbing skins began glopping up by noon as the snow surface warmed on solar aspects. 

Western slopes were stripped, with cross loaded gullies holding wind. Previous tracks were covered in open areas at higher elevations on North and East aspects. A breakable wind crust was observed in open areas on wind effected, northern slopes.

Snowpack height is highly variable. Depths differ dramatically, even on the same slope. In shallower areas, we have poor structure with hard slabs sitting atop weak, faceting snow. Deeper areas continue to have persistent weak layers in the mid pack. These buried weak layers continue to fail and fully propagate in long column tests.  

We remotely triggered an avalanche on small grained facets which sat underneath a hard slab from 1/17. This avalanche had a two foot crown.  

Photo 1: Remote triggered avalanche.

Photo 2: Hard slab overlies weak faceted snow.

Photo 3: Weak layer from avalanche of small grained facets.

 

  

Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
Clear
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
Northwest
Accumulation rate: 
None
More detailed information about the weather: 

A beautiful day. Clear skies with temps warming to the upper twenties by mid day. Light Northwest winds with gusts into the mid teens.