Persisent weak layers in Jewel Basin

Location Name: 
Jewel Basin
Swan Range - West Side (Flathead Valley access)
Date and time of observation: 
Wed, 11/08/2017 - 12:00
Location Map: 

Red Flags: 
Obvious avalanche path

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

Snow depths up to 110 cm.  The snowpack consists of a relatively homogeneous mid to upper pack, with a mix of crusts or crust/facet layers near the ground.  The buried "Halloween crust" is most widespread above ~5,500 feet on northerly and east aspects, we found good bonding above the crust (<.3mm rounds) and lurking facets of varying size and hardness below the crust on some higher, northerly slopes. A potentially scary start to the snowpack exists in the northeasterly-facing Jewel Basin start zones, where recent NE winds have scoured the snowpack back down to the Halloween crust, leaving it thin and faceting below. Snow depths in these areas were less than a foot, comprised of a 2-3 cm 1Finger crust capping Fist hard, 1mm facets. The crust showed minor cracking and collapsing under foot.  These upper start zones could harbor future persistent slab problems if we go into a prolonged SW loading event.   

We also observed .5mm near surface facets forming in wind-sheltered slopes, worth monitoring with our next load.

There were pockets of drifted and upside-down snow from last weekend's northeasterly winds, but we weren't able to produce any signs of instability from ski cuts or stomps.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 

November 8, 2017 - Persistent Weak Layers in Jewel Basin

Weather Observations
Blowing Snow: 
Air temperature: 
Below Freezing
Wind Speed: 
Calm (No air motion)
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 
Precip Rate: 
S -1; very light snowfall, trace to 0.5cm/hour