Avalanche Forecast
Issued: Mar 4th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
wlewis,
Avalanche Canada
Avoid wind loaded features on all aspects, winds are expected to vary. Steer clear of sun affected slopes if skies clear, even short bursts of sunshine may increase reactivity.
Deep persistent weak layers continue to be a concern in this region. Read about managing this problem in our latest Forecasters' Blog.
Summary
Confidence
Avalanche Summary
On Thursday and Friday, storm and wind slabs were reported to size 2.5 from natural and human triggers. Operators reported rapid loading due to winds at higher elevations but observations have been limited due to visibility and weather. We expect a natural cycle to have occurred primarily in wind loaded features.
Deep persistent slab avalanches were observed over a week ago, occurring during the very windy arctic outflow event.
Snowpack Summary
Variable winds have redistributed recent storm snow into deeper deposits on many aspects. This storm snow sits over wind effected surfaces and a thin sun crust on steep south facing slopes.
Around 40-90 cm deep a layer of small surface hoar exists in lower elevation sheltered areas. Elsewhere heavily wind effected surfaces exist, with faceted (sugary) snow from the late February Arctic blast. Reports suggest this interface has not yet been reactive.
The remainder of the mid-snowpack is considered generally strong with a small surface hoar layer from mid February that appears to be spotty and is not producing avalanche activity.
A layer of large and weak facets that formed in November sits near the base of the snowpack. Although the likelihood of triggering this layer is low at this time, the consequence of doing so remains very high. This layer is most likely to be human-triggered in thin, rocky slopes at alpine and upper treeline elevations.
Weather Summary
Saturday Night
Light easterly winds, gusting moderate. Freezing levels below valley bottom.
Sunday
A mix of sun and cloud. Light easterly winds. Freezing levels below valley bottom, alpine high of -8 °C.
Monday
A mix of sun and cloud. Light to moderate southerly winds. Freezing levels below valley bottom, alpine high of -6 °C. Possible flurries.
Tuesday
Mostly cloudy with moderate southwest winds. Freezing levels below valley bottom, alpine high of -4 °C. Flurries.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
Problems
Wind Slabs
Recent storm snow has been affected by variable winds. Expect deeper wind affected deposits on many slopes. Sheltered terrain produce loose dry avalanches - be prepared to manage your sluff.
Additionally areas that see clear skies and strong sun should avoid sun affected slopes. Surface snow may rapidly lose cohesion.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth, but smaller avalanches in motion have the potential to step down creating very large avalanches. Suspect terrain for human triggering includes steep, shallow and rocky terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 5th, 2023 4:00PM
