Observation: Black Canyon

Observation Date
01/23/2018
Observer Name
Kobernik-Osborne

Region:

Location Name or Route
Black Canyon to Reeder Canyon
Weather
Sky
Clear
Wind Direction
Northwest
Wind Speed
Light
Snow Characteristics
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments

Slopes facing the sun became damp.  Otherwise, cold powder remains on all other slopes.  Very little wind effect still.  Most places where we jumped off the machines, our boots sank right through to the ground.  Overall depths are around 2 feet or a bit more in the highest terrain.

Red Flags
Red Flags
Collapsing
Poor Snowpack Structure
Red Flags Comments
My partner was able to get a north facing slope at about 10,500' to collapse and fracture but it didn't release when he rode a snowbike near it.
Avalanche Problem #1
Type
Persistent Slab
Trend
Same
Problem #1 Comments

The weak snow near the ground remains the greatest concern.  The last storm didn't really add a whole lot of weight on top of the old weak snow.  The wind did not drift much snow either.  These two factors are why we didn't see any avalanches during the last storm.  However, the weak snow is not going away yet and will need to be taken into account during future storms.

Snow Profile
Aspect
Northeast
Elevation
10400
Slope Angle
30
Comments

We performed a couple of stability tests today, one formal and one informal. 

The formal one was an Extended Column Test that propagated after one tap from the shoulder (ECTP-21).  Very clean shear on top of the Christmas facets.

We then widened up the pit and rode a snowbike over the top and had similar results.

Video

This weak snow near the ground makes me nervous.  Chances for triggering an avalanche are decreasing right now but it would still be possible.  There is enough danger to keep me off many steep slopes on the north half of the compass.

Obviously, the danger will increase when we add more snow on top of this weak snowpack structure.

Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate
Snow Profile Coordinates