Avalanche Forecast

Archived

Apr 1st, 2021–Apr 2nd, 2021

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

South Rockies.

Sunny skies and rising freezing levels will increase the likelihood for both wet loose avalanches and cornice failures throughout the day on Friday. Avoid large slopes facing the sun and slopes exposed to large cornices; especially during the heat of the day.

Confidence

High -

Weather Forecast

THURSDAY NIGHT: Clearing / Strong, southwest ridgetop wind / alpine low temperature -9 / Freezing level 2100 m.

FRIDAY: Sunny / Moderate, southwest ridgetop wind / alpine high temperature 5 / Freezing level 2400 m.

SATURDAY: Sunny / Light, southwest ridgetop wind / alpine high temperature 7 / Freezing level 2500 m.

SUNDAY: Snow/rain; 3-5 mm. / Strong, southwest ridgetop wind / alpine high temperature 4 / Freezing level 2100 m.

Avalanche Summary

On Wednesday, no new avalanches were reported in this region.

Snowpack Summary

The 20-40 cm of recent storm snow appears to be bonding well to previous melt freeze crusts from mid March that were found on all but steep north facing alpine slopes. Strong southeasterly winds have been transporting snow and forming new wind slabs in lee features. Cornices are reported to be large and looming. With rising freezing levels and sunny skies, snow will likely lose strength as it becomes moist on all aspects at lower elevations and solar aspects at upper elevations.

The mid-pack is firm and well settled. Some faceted snow and a decomposing melt-freeze crust can be found near the base of the snowpack.

Terrain and Travel

Be alert to conditions that change with elevation and sun exposure.
Be careful as you transition into wind affected terrain.
Back off slopes as the surface becomes moist or wet with rising temperatures.
Pay attention to cornices and give them a wide berth when traveling on or below ridges.

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.

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.