South Columbia

Ridgetop wind speeds are uncertain for Tuesday. If northerly winds are strong, new wind slabs can be expected on all aspects.

Moderate - Wind speed and direction is uncertain on Tuesday

Tuesday: Mix of sun and cloud / Moderate north winds / Alpine temperature at -25Wednesday: Clear skies / Moderate north winds / Alpine temperature at -18Thursday: Mix of sun and cloud / Strong northwest winds / Alpine temperature at -14

On Sunday a few size 1 skier-triggered wind slabs were observed in higher elevation wind-exposed terrain. I'd expect a new round of wind slab activity in response to new snow and wind on Sunday night and Monday. Northerly winds on Tuesday may promote a reverse loading pattern increasing the likelihood of wind slab activity on a variety of aspects.

Up to 20 cm of low density snow fell on Sunday night and Monday. Moderate to strong southwest winds are expected to have shifted these fresh accumulations into wind slabs at treeline and above. Recent snow has covered old, thicker wind slabs from previous wind events. The mid-December facet/surface hoar persistent weakness can be found buried 70-120 cm deep and is generally considered dormant. However, we are still receiving occasional reports of sudden results, suggesting that it has to potential to propagate into a large avalanche if triggered, particularly in shallow spots where this layer is closer to the snow surface. The lower snowpack is well bonded and features a thick rain crust near the ground.