Avalanche Forecast

Archived

Mar 4th, 2022–Mar 5th, 2022

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, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Northwest Coastal.

With fair weather comes the desire to get after it. However, there's some interesting things going on in the upper snowpack so listen to what it is telling you and continue to investigate for the existence of buried weak layers on the features you are riding.

Confidence

Moderate -

Weather Forecast

Friday night: Mainly clear. No precipitation. Light winds from the north. -9°C in the alpine.

Saturday: Mainly sunny. No precipitation. Light winds from the north. A low of -9°C and a high of +3°C in the alpine. Freezing levels rising to 1400m.

Sunday: Mainly sunny. No precipitation. Moderate winds from the north. A low of -5°C and a high of +3°C. Freezing levels rising above 2000m.

Monday: Mainly sunny. No precipitation. Light winds from the north. A low of -5°C and a high of +2°C. Freezing levels at 1500m.

Avalanche Summary

There have been isolated, skier reactive slab avalanches to size 1.5 reported on weak, feathery surface hoar crystals buried 25-50cm at treeline and in the lower alpine.

A professional operation reported a slab avalanche being triggered by a wet loose avalanche from above on Thursday.

Snowpack Summary

There's a lot going on in the upper snowpack. Careful assessment is recommended.

There is now a crust on the surface at lower elevations and on solar aspects at treeline.

Feathery, weak surface hoar crystals buried around February 26th are now found down 25-50cm most prominently at treeline elevations. There have been reports of this layer being reactive to skier traffic.

A thick crust buried in mid-February is now found down 60-100cm. Though there has been little avalanche activity reported on this layer, it should be treated with suspicion.

The lower snowpack is effectively bridged by the layers above and we do not expect avalanches to be triggered in the lower snowpack at this time.

Terrain and Travel

Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Surface hoar distribution is highly variable. Avoid generalizing your observations.
Avoid travelling on slopes below cornices.
Firm cornices can pull back into flat terrain at ridgetop if they fail.

Problems

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.

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.