Avalanche hazard will increase with warm temperatures and sunshine. Persistent layers in the upper snowpack are sensitive to triggering.
Weather Forecast
Freezing levels remained high overnight but are expected to drop to 2000m today. Precipitation will taper off later this morning with a mix of sun and cloud. Expect moderate westerly ridge winds with gusts to 55km/hr and an alpine high of 0 C. Typical spring temperatures resume tonight as freezing levels drop to 1400m.12 cm of snow for Sunday.
Snowpack Summary
Freezing levels above 2200m overnight and 10mm of rain early this morning. Suspect moist and warm upper snowpack. Lee loading from strong S winds. At higher elevations, up to 70cm of settling storm snow sits over several persistent week layers in the form of crusts, surface hoar and facetted layers which are reactive to light loads such as skiers.
Avalanche Summary
Artillery avalanche control in the highway corridor resulted in several size 20-2.5 slab avalanches. Avalanches were moist in character and failed on a crust in the upper snowpack. Several Natural loose wet and slab avalanches were observed in the highway corridor and adjacent backcountry areas during the warmest part to the day.
Confidence
Freezing levels are uncertain
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.