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 5th, 2021–Apr 6th, 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 unlikely.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.

Regions

Northwest Inland.

Watch for cornices and reactive slabs near ridgetops and lee terrain. 

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

MONDAY NIGHT: Flurries, up to 5 cm, moderate southwest wind, treeline temperatures around -5 C with freezing levels dropping below 500 m.

TUESDAY: Scattered flurries with up to 15 cm of new snow accumulating by the end of Tuesday, moderate southwest wind, treeline temperatures up to -1 C with freezing level up to 900 m.

WEDNESDAY: Mix of sun and cloud with some light flurries, light west wind, treeline temperatures around -4 C and freezing level dropping to valley bottom.

THURSDAY: Flurries arriving late in the day, increasing southwesterly wind, treeline temperatures below -3 C with freezing level at valley bottom.

Avalanche Summary

Strong winds contributed to intense wind-loading in areas on Sunday with fresh wind slab avalanches to size 2 failing in immediate lee features.

Reports from Saturday included a few isolated avalanches with some size 1-2 cornice failures, one size 2 wind slab on a southeast aspect, and one size 2 wet loose avalanches on a south-facing slope.

Snowpack Summary

Wind slabs formed by light amounts of recent snow and southwesterly winds may linger below alpine ridgetops. A firm crust exists at lower elevations. Cornices are large and looming at this time of year.

Buried 70-120 cm. deep, a spotty layer of surface hoar may exist on sheltered north aspects, but no recent avalanches have been reported on this layer. 

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 within much of the region and have 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

  • Be careful as you transition into wind affected terrain.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Avoid exposure to slopes that have cornices overhead.
  • Dial back your terrain choices if you are seeing more than 20 cm of new snow.

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.