Avalanche Forecast
Issued: Mar 3rd, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Cornices and Loose Wet.
swerner,
Avalanche Canada
The March sun can really pack a punch and destabilize the upper snowpack. Natural and human triggered avalanches remain possible and give large and looming cornices a wide berth from above and below.
Summary
Confidence
Low - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack. Uncertainty is due to the limited number of field observations.
Weather Forecast
Change is in the air with a strong ridge set up through the weekend. This will bring clear and sunny skies, light northerly wind, and rising freezing levels.
Thursday Night: Some cloud cover with light northwest winds. Freezing levels dropping to 800 m.
Friday/ Saturday: Sunshine with some clouds. Ridgetop wind light to moderate from the northeast and alpine temperatures near 0 degrees. Freezing levels (diurnal) 1000 m overnight and 1500 m during the day.
Sunday: Sunny skies with freezing levels rising to 2000 m during the day. Ridgetop wind moderate from the North and alpine temperatures possibly rising to +2 degrees.Â
Avalanche Summary
No new reports by Thursday afternoon.Â
On Wednesday, wet loose avalanches up to size 1 were easily triggered by skiers. No new natural avalanche activity.
On Tuesday, a skier triggered storm slab size 1 was reported from a northeast aspect at treeline. Wet loose avalanches were easily triggered below treeline up to size 1.Â
On Monday, several storm slabs were reported up to size 2. This followed a widespread natural storm slab avalanche cycle on Sunday. Skier-controlled storm slabs were triggering remotely and propagating widely at treeline and below as shown in this MIN report. Natural avalanche activity will likely continue through Wednesday with reactive storm slabs in the alpine and upper treeline and loose wet avalanches below treeline.
Snowpack Summary
30-60 cm of new snow storm snow has become saturated by rain to mountain top on the North Shore range. Upper treeline and areas with alpine may still hold dryer snow and a reactive storm slab. The recent snow sits over a variety of weak surfaces that were buried mid-February including facets, surface hoar, and sun crust, to which it appeared to be bonding poorly initially during the storm. I'd still be suspicious of this interface at upper treeline or alpine locations that aren't capped by a solid crust. Check out the Sea to Sky Forecast to learn more about the recent reactivity on this layer in the adjacent region.
50-80 cm below the surface, a 30cm thick crust caps the underlying snowpack which is well settled and strong.
Terrain and Travel
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Keep in mind that wet avalanches can be destructive due to their high density.
- Cornices become weak with daytime heating or solar exposure.
- Avoid exposure to steep, sun exposed slopes, especially when the solar radiation is strong.
Problems
Storm Slabs
Storm slabs may be reactive to human triggering, especially in steep or convex terrain and wind-loaded areas in the alpine, especially where they sit above a firm and slippery crust. Wet slabs may be seen at treeline elevations and on solar aspects as the sun and warming destabilize the upper snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Looming cornices have grown large during the recent storm. They could pose threat from above and below and weaken when the sun is out.
Aspects: North, North East, East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
The warm spring sun may easily trigger loose wet avalanches at all elevations, especially on south facing slopes.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 4th, 2022 4:00PM
