Primary Problem

Wind slabs form where wind has deposited or drifted snow. You will find them on lee aspects, generally near ridge lines, around terrain features and in ‘cross-loaded’ features like vertical ridges, couloirs and gullies. Wind slabs may remain reactive for up to a week after the wind event has ended.

Secondary problem

A persistent slab is any slab formed over a persistent weak layer, in our case, depth hoar. These slabs are hard to predict, often are triggered from the middle or low on the slab, and can propagate over large areas and across terrain features traditionally thought of as safe zones, like ridges, benches, and low angle terrain. The problem can last for weeks or months.

Snowpack discussion

Today’s danger rating increases to Considerable after yesterday’s late evening wind event with snowfall that brought significant accumulation to the alpine zone near ridgelines. Wind slab is the primary problem. The winds on top of Mount Apharwat deposited newly fallen snow onto the old snow surface, and this is our main concern today. Ski cutting during the early hours of the storm yesterday revealed energy in this newly fallen layer that has the ability to propagate across slopes. Likely areas for wind slab danger are NW, N, NE, and E aspects. Persistent slabs remain in the advisory today as well with newly fallen snow on top of an already significant snowpack sitting on depth hoar just above the ground. Below treeline the danger rating increases to Moderate with newly fallen snow in the last 24 hours. Phase 2 of the gondola is closed today until further notice.

Weather discussion

Cloudy with snow showers today. Light southerly winds with temperatures remaining below freezing.