Avalanche Forecast

Archived

Mar 22nd, 2024–Mar 23rd, 2024

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Northwest Coastal, Boundary, Kitimat, Nass, Rupert, Seven Sisters, Shames, Stewart, Howson, Ningunsaw, Ningunsaw, Ningunsaw.

Watch for changing surface conditions with sun and warm temperatures,

The search for dry snow may draw you to high north facing terrain, be aware buried weak layers may remain reactive here.

Confidence

Moderate

Avalanche Summary

Loose wet avalanches were observed from steep solar slopes over the last 2 days. Avalanches ranged from size 1-2.5, with the larger avalanches scouring to ground.

On Wednesday, a few persistent slab avalanches were observed to size 3, on alpine south-facing slopes, liikely triggered by daytime warming. Skier-triggered avalanches (size 2) also occurred in shallow rocky areas which stepped down to the persistent slab.

Snowpack Summary

A widespread melt-freeze crust exists on the surface in most areas. The crust may soften throughout the day at lower elevations and on south-facing slopes. Dry snow can still found on true north-facing alpine slopes. At lower elevations below the surface crust, the snowpack is likely moist or wet to ground from recent warming.

A layer of weak, faceted crystals over a crust, or surface hoar, remains a concern for human triggering at treeline and alpine elevations, buried approximately 90-180 cm deep. This layer is harder to trigger as it becomes deeper, but has the potential to produce large avalanches.

Weather Summary

Friday Night

Clear skies. 20-30 km/h east ridgetop wind. Freezing level drops to valley bottom.

Saturday

Sunny. 20-30 km/h northeast ridgetop wind. Treeline temperature +4 °C. Freezing level rising to 2000 m. Overnight refreeze expected.

Sunday

Sunny. 20 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level remains around 1700 m.

Monday

Cloudy. 20 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level remains around 1200 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
Be aware that wet activity at low elevations is a classic situation for step-down failures in deeply buried persistent weak layers.

Problems

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.