Avalanche Forecast

Issued: Jan 17th, 2023 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Persistent Slabs and Deep Persistent Slabs.

CG, Avalanche Canada

Glacier.

Rogers Pass and the surrounding Columbia Mtns have a weak basal snowpack this season, which is making all snow professionals work hard to identify hazards not normally seen in these areas.

Drop your desires a notch; ski/ride to the conditions we have this year.

Summary

Confidence

Moderate

Avalanche Summary

The weekend's natural avalanche cycle has passed, and in its wake we have observed isolated sz 1.5 to 2.5 soft slabs along the highway corridor, mostly from steep S'ly aspects.

Snowpack Summary

Two surface hoar (SH) layers, present in the upper 40cm, are potential failure planes in areas where the surface snow has become slabby (ridgecrests, immediate lee features). 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

Continuing mix of sun, cloud, and isolated flurries, with light winds at ridgetop.

Wed: mainly cloudy, trace to 4cm, Alp high -6*C, 1200m FZL, light SW wind

Thurs: mix of cloud and sun, trace snow, Alp high -8*C, 1000m FZL, light W wind

Terrain and Travel Advice

Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Use caution when approaching steep and rocky terrian.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

Problems

Persistent Slabs

The Jan 3 surface hoar (5-10mm) is buried ~40cm and is more reactive at ridgeline or in immediate lee features, where wind has stiffened the surface. If triggered, this slab has the potential to step down to the deeper persistent slab.

Aspects: All aspects.

Elevations: All elevations.

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 particularly cautious in steep, rocky areas with thin snow coverage, where the majority of the snowpack is weak and faceted.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Jan 18th, 2023 4:00PM