Rain this morning will destabilize the already weak snowpack. Avoid avalanche paths and steep openings below treeline where the snowpack is mushy & has lost its structure
Weather Forecast
Rain will start this morning, turning to snow this afternoon as freezing level drops. Possible snow amounts to 8cm with an Alpine high of 3 deg & southwest ridge wind @ 20kph gusting 45. Freezing level will spike to 2200m this AM then drop to 1300m tonight. Temps stay cool for the next couple of days however they go back up to 3600m by Thursday
Snowpack Summary
Warm temps and 3mm of rain yesterday have created an isothermal and moist snowpack. Thin surface crusts forming overnight are weak and break down quickly. Multiple crusts in the top meter of the snowpack provide sliding surfaces. Dry snow exists on steep N aspects in the high Alpine.
Avalanche Summary
Sunday there was a natural avalanche cycle in the park triggered by poor overnight freeze, daytime highs of +11, 3mm of rain and strong solar. Destructive wet avalanches were observed to size 3, the most notable were glide crack releases & low elevation slabs. Saturday night a south facing avalanche path on Cougar Mtn ran sz 3 to the end of runout.
Confidence
Freezing levels are uncertain
Problems
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.
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.