Sunny skies and freezing levels as high as 3500 m are continued Wednesday. As the snowpack deteriorates, natural avalanche activity is to be expected. Solar induced wet slabs may be large and run full path.
Confidence
Fair - Timing or intensity of solar radiation is uncertain on Wednesday
Weather Forecast
The weather pattern will begin to change tonight as a dominating ridge of high pressure will start to break down. This will allow a strengthening, moist SW flow to enter the region. Wednesday: Freezing levels will continue to be near 3500 m, with sunny skies and light-moderate Southerly winds. Thursday: Light precipitation should begin later Wednesday night, while Thursday may bring moderate-heavy amounts. Freezing levels will fall 1800 m. Ridgetop winds light gusting moderate from the West. Friday: Lingering, light precipitation through the day. Freezing levels will rise to 2000-2500 m, with sunny skies in the afternoon.
Avalanche Summary
Some loose snow activity on a SE facing slope was reported, but, there is surprisingly little avalanche activity in the region currently.
Snowpack Summary
Spring like weather, and conditions have promoted settlement and bonding within the upper snowpack. Below this a cohesive slab 60-120 cm (depending on the drainage) sits on the March 27th interface. Our field team was out in the region on Tuesday; they were able to find the March 27th interface down around 95cm but test profiles did not produce any results on this layer. At 1900 m on a NE aspect the upper 10cm surface snow has become moist, below this the snow is still dry. All other aspects the snow has become moist. Without significant re-freeze the snowpack may continue to deteriorate through Thursday. Natural avalanches are expected. Large cornices loom over many lee slopes, and could trigger slopes below. Glide cracks are a concern, be sure to give them a wide berth as they are very sensitive and could fail at any moment.
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.
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.