Avalanche Forecast
Issued: Mar 15th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Cornices and Deep Persistent Slabs.
swerner,
Avalanche Canada
The March sun packs a punch and can quickly destabilize the snowpack on solar slopes.Storm slabs may continue to be reactive to human triggering, especially on leeward wind-loaded slopes.
Summary
Confidence
Avalanche Summary
No new reports on Wednesday at the time of publishing.
On Tuesday, several skier-controlled slab avalanches (size 1.5) were reported on wind-loaded features at treeline and above. Dry loose sluffing was noted from steep northeast terrain up to size 1.5.
On Monday, several natural cornice falls were reported in the northern part of the region up to size 2.5.
On Sunday, a natural large size three, wind slab avalanche was observed. It started in a cross-loaded feature in the alpine and it may have stepped down to weaker buried layers.
Natural and human-triggered avalanche activity may occur throughout the week with rising freezing levels and solar radiation.
Snowpack Summary
Surface snow will likely become moist on solar aspects during the day. 30 to 50 cm of recent storm snow sits above a sun crust on steep solar aspects, dryer low-density snow, and older faceted snow in sheltered areas. Much of this has been redistributed into reactive wind slabs at treeline and above. It has also built upon the large cornices that have already formed.
The mid-snowpack is well consolidated.
There is a widespread weak layer of large sugary facets at the bottom of the snowpack. Recent avalanche activity on this layer has been confined to northern parts of the region in the Chilcotins. This layer remains a concern in shallow snowpack areas.
Weather Summary
Wednesday Night
Clear. Alpine temperatures near -11. Wind from the west 10 km/hr and freezing level valley bottom.
Thursday
A mix of sun. Alpine temperatures near -4. Winds southeast 10-20 km/hr. Freezing level 1600 m.
Friday
A mix of sun and cloud. Alpine temperatures near -3. Wind southeast 10-20 km/hr. Freezing level 1800 m.
Saturday
A mix of sun and cloud. Winds 10-20 km/hr from the south. Alpine temperatures near -2 with freezing levels 1900 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Problems
Storm Slabs
30 to 50 cm of new snow and strong south wind have formed storm slabs. These slabs may have a poor bond to the underlying crust.
Moderate to strong southwest winds have formed reactive wind slabs on lee slopes at treeline and above.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large and fragile. Solar radiation will weaken them further and cornice failures act as heavy triggers on slopes below.
Strong solar radiation may weaken the surface snow creating wet loose avalanches from steep solar slopes.
Aspects: North, North East, East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of weak facets sits near the base of the snowpack. This layer is most likely to be problematic in steep, wind-loaded terrain where the snowpack depth varies from thick to thin. Especially in the northern part of the region around the Chilcotins, Birkenhead, and Hurley.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 16th, 2023 4:00PM
