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 23rd, 2021–Mar 24th, 2021

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

Regions

South Coast.

Additional new snow and wind Tuesday night through Wednesday morning will promote storm and wind slab formation at upper elevations.

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

TUESDAY Night: Flurries, accumulation 5-10 cm, moderate west wind, treeline temperatures around -2 C.

WEDNESDAY: Cloudy with flurries bringing 5-15 cm of snow throughout the morning, 30-50 km/h southwest wind, freezing level 1200 m with treeline temperatures around -1 C.

THURSDAY: Cloudy with sunny periods, light northeast wind, freezing level climbing to 1500 m with treeline temperatures near 1 C.

FRIDAY: Cloudy with sunny periods, light northwest wind, freezing level around 1000 m with treeline temperatures -1 C. 

Avalanche Summary

On Monday there were some reports of size 1.5-2 human triggered avalanches in the Seymour backcountry (30-60 cm thick). See the photos here and here. Additionally there were reports of several size 1.5 explosives triggered storm slab avalanches.

Widespread storm slab avalanche activity was reported on Sunday, and preliminary reports from Monday suggest they were still reactive to human triggering. On Sunday numerous size 1-2 natural slab avalanches were observed in the North Shore mountains. These avalanches were mostly 20-30 cm thick and ran on a crust layer.

Snowpack Summary

By mid morning Wednesday there could be 10-25 cm of new snow to add to the 35-45 cm of snow from Sunday which has likely settled and bonded to the old snow surface below. Along ridgelines, cornices are large and always have the potential of failing or being triggered from the weight of a human.

Terrain and Travel

  • Watch for avalanche hazard to increase throughout the day.
  • Exercise caution on steep, unsupported slopes.
  • Be careful as you transition into wind affected terrain.
  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

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.