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, 2023–Mar 4th, 2023

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

Regions

Long Range Mountains, Corner Brook, Gros Morne, Northern Peninsula.

Wind slab is the main concern for the weekend. Watch for reactive wind slabs in lee and cross-loaded terrain features at upper elevations.

Confidence

High

Avalanche Summary

Wind slab avalanches size 1-2 have been observed over the last few days on north to east facing slopes in the alpine. Some of them are suspected to have been triggered by cornice falls.

Recent snowpack test results and signs of instability like shooting cracks reported in recent MINs also suggest instability in wind slabs.

Snowpack Summary

Variable snow conditions exist at upper elevations due to extensive wind affect by sustained moderate west to northwest winds. Soft snow can still be found in sheltered areas like in trees, gullies and bowls.

A widespread near-surface crust has been described in nearly every MIN report this week (thank you!). It sits on the surface in scoured, windward features; an average of 10 cm deep in sheltered areas; and up to 30 cm deep in wind-loaded areas. Some faceting has been observed above the crust which has created a weak layer for overlying wind slabs to fail.

The snow below is a mix of dense wind affected snow layers at higher elevations. At lower elevations you may find another thin melt freeze crust 50+ cm deep. The lower snowpack is likely dense and well bonded from warm temperatures, rainfall and subsequent refreezing.

Weather Summary

Friday night

A trace of snow. Moderate to strong northwest wind. Alpine low -14 C.

Saturday

A mix of sun and cloud with isolated flurries bringing a trace of snow. Moderate to strong northwest wind. Alpine temperature -15 C.

Sunday

5-10 cm of new snow. Moderate to strong northwest wind, switching northeast in the evening. Temperatures warming through the day, reaching 0 C in the alpine by late evening.

A "backdoor warm front" associated with an atypically tracking low pressure center moving west-to-east is casting great uncertainty on the weather forecast beyond the weekend. Weather models vary greatly from one run to the next so stay tuned for updates. Likely weather features include above zero temperatures, mixed precipitation and strong east to northeasterly winds.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Seek out sheltered terrain where new snow hasn't been wind-affected.
  • Expect slab conditions to change drastically as you move into wind exposed terrain.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Watch for areas of hard wind slab on alpine features.
  • Approach lee and cross-loaded slopes with caution.
  • Wind slabs may be poorly bonded to the underlying crust.

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.