Recent avalanche activity in the Dogtooth Range suggests the avalanche danger may be higher in northern parts of the region.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Expect a mix of sun and cloud throughout the forecast period. Ridgetop winds should remain mainly light with daytime freezing levels hovering around 800m.
Avalanche Summary
Reports from Monday include 2 skier-triggered size 2 wind slab avalanches in the Dogtooth Range. Buried surface hoar beneath the 35 cm thick wind slab is expected to have increased the reactivity of the avalanches which ultimately stepped down to the deeper mid-December facet layer. One avalanche occurred on a northeast aspect while the other occurred on a west aspect. They were both, however, cross-loaded alpine features.Moving forward, lingering wind slabs are expected to remain a concern, especially where the slabs sit over a preserved layer of surface hoar. Wind slabs should be expected in steep, unsupported or convex leeward terrain features. In some places, moderate outflow winds may have caused reverse loading and formed thin new wind slabs in recent days.
Snowpack Summary
25-50 cm of recent snow typically overlies the variable mid-January interface which consists of wind affected surfaces in exposed terrain, surface hoar in sheltered areas, and/or widespread faceted old snow. The bond between the new snow and the old surface is generally gaining strength with colder temperatures that followed the storm but weaknesses are lingering, especially where surface hoar is preserved. Strong southwest winds during the storm and moderate southwest winds following the storm have redistributed the new snow and developed wind slabs in leeward terrain features. The mid-December facet/surface hoar persistent weak layer can be found buried 50-100 cm deep and is generally considered dormant. However, a few storm slab and wind slab avalanches have recently stepped down to this layer in isolated areas. This layer remains an isolated concern for shallow snowpack areas where the layer is closer to the snow surface. With the next storm or period of warming, this layer could wake up and create a more widespread problem.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.