Manto nevoso

Observation: Ben Lomond

Derek DeBruinOgden
Vedi sulla mappa

Quick report

Old snow depths ranged 20-50cm, with a set up similar to yesterday's obs from the Powder Mountain periphery: wet throughout (where not frozen), multiple crusts, and facets of varying size and rounding mixed in. We did find snow depths up to 1m in a few deposition zones immediately below steep (50-60 degrees) gullies and cliffs, though these were the exception.

The ample wind regularly moved the surface snow, and there was a bit of spin drift. We didn't note any hard slab formation, though we were certainly on the fetch side of the mountain. There was some soft slab cohesion, but with new snow seeming to bond well to the underlying crust, we did not experience any reactivity under foot. However, we did not travel as high as the summit ridge line, so can't comment much about the upper elevations.

Pictured below are 1) snow surface around 8000ft with a bit of a wind lip visible and some wind-scoured surface and 2) upper elevation W facing slopes above mid elevation rocky terrain.

Snowpack

Snow surface was largely new snow--rimed forms and graupel--on bare ground. The snow line was as low as 5500ft or so, with 1cm or so accumulated that more or less persisted through end of day. Snow amounts gradually increased with elevation, with 10-15cm of HN on the west slopes of Ben Lomond in the mid-elevation band. Snow density decreased with elevation, but all of it was at least a bit moist.

 

There were pockets of old snow on protected N and NW slopes in drainages shaded by cliffs. The old snow was as crusty and layered as would be expected from repeated thermal and rain events. In many places it resembled firn and occasionally had even consolidated into alpine ice. The treed W/NW facing slopes below the summit held the only continuous old snow surface.