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

Apr 11th, 2023–Apr 12th, 2023

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

Regions

Sea To Sky, Brandywine, Garibaldi, Homathko, Spearhead, Tantalus, Sky Pilot.

Don't let good weather lure you into dangerous terrain.

Dry storm snow may be seeing its first test of strong sun, and avalanche danger could increase rapidly.

Confidence

Moderate

Avalanche Summary

A natural avalanche cycle occurred over the weekend. Storm and wind slabs up to size 3 were observed at treeline and above. Cornice failures initiated large slabs on the slope below. Check out this MCR for a report from the Pemberton Icefield.

On Monday, explosive control in the Whistler area produced numerous large (size 2-3) storm and wind slabs, predominantly from wind-loaded alpine terrain. Check out Wayne Flann's blog for photos of these avalanches.

Looking forward to Wednesday, we suspect that rider-triggerable wind slabs may still be found at treeline and above. Strong sun could rapidly increase avalanche danger. Be cautious during periods of strong solar input, especially on slopes with large cornices overhead.

Snowpack Summary

Up to 70 cm of recent storm snow was accompanied by strong to extreme southerly winds, forming wind slabs on west through east aspects at treeline and above. These winds have also scoured exposed windward slopes. A crust exists on or near the surface at lower elevations and to ridgetop on solar aspects.

A crust from early April can be found down 50 to 80 cm on all solar aspects and at treeline and below on north-facing terrain. Below this crust, the snowpack is generally well-settled.

Weather Summary

Tuesday night

Clear periods. Alpine temperatures drop to a low of -9 °C. Ridge wind light from the west. Freezing level at valley bottom.

Wednesday

Sunny with cloudy periods. Alpine temperatures reach a high of -3 °C. Ridge wind light from the north. Freezing level rises to 1600 metres.

Thursday

Mainly cloudy with scattered flurries, up to 5 cm accumulation. Alpine temperatures reach a high of -5 °C. Ridge wind 15 to 30 km/h from the southwest. Freezing level rises to 1200 metres.

Friday

A mix of sun and cloud. Alpine temperatures reach a high of -3 °C. Ridge wind 10 to 40 km/h from the southwest. Freezing level rises to 1500 metres.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be alert to conditions that change with elevation and sun exposure.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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 Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.