Avalanche Forecast

Archived

Mar 27th, 2024–Mar 28th, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Northwest Coastal, Boundary, Stewart, Ningunsaw, Ningunsaw, Ningunsaw.

Danger is expected to be highest during the warmest parts of the day.Human triggering remains a concern with buried persistent weak layers.

Confidence

Moderate

Avalanche Summary

Tuesday, a few loose wet avalanches were observed in the north of the region, occurring on steep sunny slopes, ranging from small to large (sizes 1 to 2).

Monday, a few glide slab avalanches were observed in the Iskut area.

Saturday, three very large (size 3) persistent slab avalanches were observed in the north of the region. They occurred on south-facing alpine slopes and were likely triggered by daytime warming.

Snowpack Summary

A thick widespread crust caps the snowpack in most areas. At lower elevations and on steep sunny slopes, the crust may soften with warming during the day or the snowpack may become isothermal.

Dry powder snow still exists on high north-facing alpine slopes and a weak layer of surface hoar is developing in sheltered terrain at treeline and above.

Various weak layers, including crusts, facets, and/or surface hoar exist approximately 40 to 80 cm deep. An additional crust and facet layer may be found 100 to 150+ cm below the surface. Lingering concern remains for human-triggering on these persistent weak layers.

Weather Summary

Wednesday Night

Partly cloudy. 20 to 30 km/h east ridgetop wind. Treeline temperature drops to around -4°C. Freezing level drops to around 300 m.

Thursday

A mix of sun and cloud. 20 km/h northeast ridgetop wind. Treeline temperature around 0 °C. Freezing level rising to 1200 m.

Friday

Sunny, 10 km/h northeast ridgetop wind. Treeline temperature around -1 °C. Freezing level rising to 1100 m.

Saturday

Mostly cloudy, 30 to 40 km/h west ridgetop wind. Treeline temperature around -1 °C. Freezing level rising to 1100 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet

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.