Forecaster Observation - McGinnis Creek, Whitefish Range

The objective today was to ride around McGinnis Creek in the Whitefish Range and assess stability of low and mid-elevation slopes. 

We dug pits on east and north aspects today.

• At around 5000 feet, we found a relatively shallow snowpack despite the 75 cm (30 inches) of new snow at this elevation.
• Total snowpack depths ranged from 100 to 165 cm (39 to 65 inches) at 5000 feet.
• We found depth hoar in both pits and with the new load from the last storm it is more reactive than prior to the storm. The last storm provided the slab ingredient (which was missing) and stability tests now reveal a potential persistent slab problem at the low and mid elevations.
• We did not observe any recent avalanches, but the storm snow could have easily masked old crowns. 
• We experienced a collapse (whumpf) of the snowpack while Todd walked over to the pit that I had already started digging on a very small and low angled (around 30 degrees) test slope on an east aspect.
• During our 2 ECTs on an east aspect, the block fell into the pit during isolation of the column (video) (ECTPV x2)
• In a pit on a west aspect, our extended column test produced fracture and propagation across the column on facets above the Jan. 19 crust with moderate force (ECTP18 at 85 cm from the snow surface).
• On another extended column test on a west aspect, the layer of depth hoar fractured and propagated across the column with moderate force (ECTP 17).

It will be important to pay close attention over the next few days to see how these deeper weak layers and weak snow (facets) near the Jan. 19 crust handle the new load, which is likely to be heavier than the previous storm with higher snow levels. Stay tuned.