Archived

Avalanche Forecast

Jan 23rd, 2023–Jan 24th, 2023

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Glacier.

Strong SW winds have been blowing through Rogers Pass, rapidly building reactive wind slabs in lee and cross-loaded areas.

These new slabs need your respect, as they have the potential to overload the persistent slabs in the upper snowpack.

Confidence

Moderate

Avalanche Summary

A field team on Connaught/Lookout triggered a sz 1 wind slab, which stepped down to the Jan 3 surface hoar. They also observed several sz 1 loose/dry avalanches on the N Face of MacDonald, running in extreme terrain.

Cheops North 4 ran sz 2 Monday morning, while Frequent Flyer ran sz 2 on Sat into the creek.

Lens Gully had a sz 2.5 run end path Mon morning.

Snowpack Summary

Reactive wind slabs are popping out at Tree-line and Alpine elevations, stepping down into the Jan 3 persistent weak layer.

The mid-pack facets are slowly rounding and gaining strength, while the basal facets and Nov 17 facet/SH/crust weakness are still reactive when isolated in snowpack tests.

Weather Summary

Unsettled weather follows Monday's cold front, bringing clouds and isolated flurries the next few days.

Tonight: mainly cloudy, flurries, trace snow, 400m FZL, moderate gusty SW winds

Tues: mainly cloudy, trace snow, Alp high -8*C, light/gusting mod W ridge winds, 900m FZL

Wed: mainly cloudy, isolated flurries, trace snow, Alp high -4*C, 1400m FZL, light W winds

Terrain and Travel Advice

Be especially cautious as you transition into wind affected terrain.
Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

Avalanche Problems

Wind Slabs

Strong S/SW winds are transporting the low density surface snow and forming wind slab at Tree-line and Alpine elevations.

Watch for these along ridge lines, lee areas and cross loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2

Persistent Slabs

This layer is buried ~40cm and will be most reactive at ridgeline or in open lee features where new wind slab has formed. If triggered, this slab has the potential to step down to the deep persistent layer.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1.5 - 2.5

Deep Persistent Slabs

The Nov 17 layer, which consists of a faceted crust and decomposing surface hoar, highlights a weak basal snowpack. Be cautious in steep, rocky areas with thin snow coverage, where the majority of the snowpack is weak and faceted.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 4