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 25th, 2023–Apr 26th, 2023

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

Regions

Northwest Inland, Kispiox, Microwave-Sinclair, Ningunsaw, South Bulkley, South Bulkley, Telkwa.

Forecast 10-20 cm of snow and strong southwesterly wind are expected to form wind slabs reactive to human triggers on lee features at treeline and above.

Concern for triggering large persistent slab avalanches remains. Avoid steep, rocky, and wind-affected areas where triggering slabs are more likely.

Confidence

Low

Avalanche Summary

Numerous naturally triggered wet loose avalanches up to size 2 were reported on all aspects/elevations on Monday.

Most professional operations are now closed which means we have very little snowpack or avalanche observation data. Please consider sharing any information or photos you have on the Mountain Information Network to help guide our forecasts.

Snowpack Summary

Forecast 10-20 cm of snow and strong southwesterly wind are expected to form fresh wind slabs on lee features at treeline and above.

A crust exists up to ridgetop on south-facing slopes and on all aspects up to approximately 1500 m.

A weak layer buried in late March is down 30-50 cm and exists as surface hoar or small facets on north facing slopes and a crust with small facets on top on sunny aspects. Test results show that this layer may be reactive to human triggers in isolated locations in the alpine where the layer is well-preserved. See MIN.

The middle of the snowpack is strong and contains numerous hard crusts. Near the ground, weak faceted crystals exist. There hasn't been avalanche activity on this layer recently, but it remains on our radar and may become active when we experience change, such as rapid loading (heavy snowfall or rain) or prolonged warming.

Weather Summary

Tuesday Night

Snow; 5-20 cm / 50 km/h south ridgetop wind / Temperature at treeline around -3 C / Freezing level 1000 m

Wednesday

Mix of sun and cloud with isolated flurries; 3-10 cm / 50 km/h southwest ridgetop wind / Temperature at treeline around 0 C / Freezing level 1300 m

Thursday

Mix of sun and cloud / 40 km/h southwest ridgetop wind / Temperature at treeline around 1 C / Freezing level 1400 m

Friday

Sunny / 10 km/h south ridgetop wind / Temperature at treeline around 8 C / Freezing level rapidly rising to 2700 m!

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.

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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

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.