Springtime snow, wind, rain, sun, and warm temps are continuing to create avalanche concerns. Monitor changes in weather and how the snowpack is becoming moist or wet before committing to a slope. Sunshine between cloudy periods could increase danger
Weather Forecast
A warm front passed through Wed night bringing warm temps and rain. Freezing levels will continue to climb to above 3000m on Fri. Cloud cover may help keep things shaded but the warm air will make all slopes moist up to ridgetop. Sat will cool slightly with 5mm of precip, likely rain with freezing levels dipping to 2000m. Sun cloudy but no precip.
Snowpack Summary
Rain and warm temperatures are penetrating the new snow we received over the last week. It was raining to at least 2500m on Thursday. The top meter is a mix of old wind slabs, rain crusts and sun crusts, all of which is becoming moist. The Feb 15 crust is now down about 110cm at 2100m. The snowpack BTL is dwindling: not much remains below 1800m.
Avalanche Summary
Avalanche activity has tapered off compared to last weekend with cooler temperatures on Tue/Wed. New snow translated into loose dry activity overnight Tue creating some large debris piles with up to sz 2 avalanches. Rain and warmth triggered snowballing and small loose wet activity only size 1 overnight Wed and during the day Thur.
Confidence
Timing or intensity of solar radiation is uncertain on Friday
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.
Wet Slabs
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.