Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Apr 10th, 2021–Apr 11th, 2021

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Northwest Inland.

Recent snow and strong winds from shifting directions which have formed fresh wind slabs on a variety of aspects at treeline and above. Watch for newly formed and reactive wind slabs as you transition into wind affected terrain and avoid slopes with large cornices overhead.

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

  

SATURDAY NIGHT: Clearing skies / Moderate, northwest ridgetop wind / alpine low temperature -13 / Freezing level valley bottom.

SUNDAY: Sunny / Moderate, northwest ridgetop wind / alpine high temperature -3 / Freezing level 800 m.

MONDAY: Sunny / Light, south ridgetop wind / alpine high temperature 0 / Freezing level 1500 m.

TUESDAY: Sunny / Moderate, west ridgetop wind / alpine high temperature 4 / Freezing level rapidly rising to 2000 m.

Avalanche Summary

A few explosive triggered wind slabs up to size 2.5 were reported in this region on Friday.

Snowpack Summary

5-20 cm. of recent snow has been accompanied by periods of strong winds from shifting directions which have formed fresh wind slabs on a variety of aspects at treeline and above. Wind slabs up to 50 cm. thick have recently been reported on lee and cross loaded slopes. 

The recent snow has covered a variety of snow surfaces, including wind affected snow, crusts on solar aspects and at lower elevations, and soft snow on sheltered slopes at upper elevations.

 Cornices are large, looming, and capable of triggering large avalanches when they fail.

The lower snowpack is reported as well settled and strong in most areas. However, weak facets exist at the base of the snowpack in the more shallow snowpack zones across the region. Where it exists, this layer has the potential to be triggered on steep, rocky slopes with a shallow or thin to thick snowpack; especially with large loads such as a cornice fall.

Terrain and Travel

  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Avoid lee and cross-loaded terrain.
  • Avoid exposure to slopes that have cornices overhead.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.

Problems

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.

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.

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.