Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Mar 3rd, 2022–Mar 4th, 2022

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

South Coast.

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. 

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. 

Avalanche Summary

No new reports by Thursday afternoon. 

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. 

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 Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.