Friday is probably the last reasonable day for a big objective for the foreseeable future, as a significant warm up is expected to begin Saturday. Watch for the odd wind slab in the alpine.
Weather Forecast
We can expect reasonable overnight temperature recovery both Thursday and Friday night before a wave of very warm air crashes into the South Rockies Saturday. FRIDAY: Freezing level beginning at 1500 m, rising to 2500 m in the afternoon, mostly clear skies, some cloud building in the afternoon, no significant precipitation, light to moderate southwest wind. SATURDAY: Freezing level beginning around 2000 m, climbing to 2500 m in the afternoon, scattered cloud cover, no significant precipitation, light to moderate southwest wind. SUNDAY: Freezing level beginning around 2500 m, climbing to around 3500 m in the afternoon, no significant precipitation, clear skies, light variable wind.
Avalanche Summary
No new avalanches have been reported in this region in the last few days, however loose wet avalanches to size 2.5 have been a regular occurrence over the last week.
Snowpack Summary
Cornices are large, fragile, and could trigger deep slab avalanches that run to valley bottoms. Monitoring the overnight freeze of the snow surface is very important during the spring. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating and solar radiation will weaken the snowpack much more quickly than it would if there is a well frozen thick crust. This is because the crust must first melt before the sun can weaken the snowpack. Deeply buried weak layers in the mid snowpack and near the ground still have the potential to wake up and become active with a rapid warm up. While unlikely, releases on these deeply buried weak layers would result in very large avalanches. Glide cracks are widespread, active, and best avoided. Low elevation and thin snowpack areas have become isothermal, meaning the snowpack is 0 degrees Celsius throughout. An isothermal snowpack is more prone to full depth wet slab avalanches during the heat of the day.
Problems
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.
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.
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.