Forecaster Observation - Skyland area, Flathead Range

Our objectives today were

1.To assess how the new snow was bonding to the old snow interface

2. Look for buried surface hoar or facets on top of an old melt-freeze crust

3. Assess wind slab distribution at upper elevations

We found the new snow to be bonding quite well to the old snow interface. We measured about 12 inches of new snow at 5000 feet and 16 inches at 7000 feet. This new snow sits atop a rain crust from last weekend (3/12-3/13). In our location the new snow lacked cohesivness. While westerly winds were moderate, this area was protected just enough from creating a wind slab. However, we noted that with a bit of warming and sunshine as the day progressed, this slab became more cohesive and began to fracture (but not propagate) in our Extended Column Tests at the new/old interface.

We did not find buried surface hoar at this location, but we found weak, sugary snow (facets) above the late February melt-freeze crust. This layer was about 60 cm (~ 2 feet) from the surface. This layer fractured and that fracture propagated across the column in all of our Extended Column Tests in all of our snowpits (so, 6 tests total) (video). It required hard force (ECTP 21, ECTP 23, ECTP 27, ECTP 21, ECTP 22, and ECTP 22) in all tests, but this illustrates the importance of digging into the snowpack. Though it requires hard force, it shows that a large load (like a cornice fall, perhaps) could trigger these deeper layers, or a trigger like a skier or a snowmobiler in a more shallow spot could also awaken this deeper layer.