Quick report
- Red Flags
- Poor Snowpack Structure
- Red Flags Comment
- <p>Poor snowpack structure with slab on top of Jan/Feb facets down 30-40 cms.</p>
Hopefully this storm materializes! The snow that fell overnight Friday into Saturday was somewhat dense and had bonded well to the existing snow surface. If we do get periods of heavy snowfall into Sunday, I am expecting the weakest snow may initially be within the storm snow. Very warm weather the past several days has left dense, warm snow at the old snow surface with widespread heat and sun crusts under the strong March sun. Avalanches involving new snow may run on these crusts.
I was seeing plenty of weak, faceted snow on northerly aspects from the Jan/Feb drought, and the slab on top has strengthened and is now more cohesive than it was a week ago.
This combination will make for some tricky snowpack assessments on northerly aspects where I think the stronger slab on top of the facets may be able to support a load on some slopes, but on other slopes where the slab isn't as strong it may be possible to trigger deeper avalanches failing on thie PWL.
Snowpack
- Instability Comment
- <p>There is weak/faceted snow down 30-40 cms on northerly aspects at the mid and upper elevations. The snow that fell on top of this weak layer 10-14 days ago is now a stronger, more-cohesive, 1F slab. I was getting full propagation extended column tests (ECTP12-15) with the failure plane this layer of faceted snow.</p> <p> </p> <p>With the potential of 1"+ of water-weight by later Sunday, we are likely to see some avalanches failing on this PWL layer. </p> <p> </p> <p>Photo below shows this structure of stronger snow on top of weaker snow. We will only be adding more of a load on top of this poor structure.</p>
Above 9,500' new snow was somewhat dry with damp snow below that elevation. New snow has bonded well to existing snow surfaces.