Avalanche Forecast

Archived

Mar 13th, 2024–Mar 14th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Regions

Sea To Sky, Brandywine, Homathko, Spearhead.

Very large avalanches will occur over the next few days.

Avoid avalanche terrain!!!

Confidence

High

Avalanche Summary

Observations from Tuesday confirm persistent slab avalanches are still a serious concern, as several size 3 natural avalanches were observed in treeline and alpine terrain in the Whistler area. There were also many size 1.5 to 2.5 storm slab avalanches over the past few days.

Looking forward we can expect warm sunny weather to cause many very large slab avalanches, as well as widespread wet loose avalanches and cornice failures.

Snowpack Summary

Rapidly rising freezing levels on Thursday will melt surfaces on all terrain except for high north-facing slopes. Over 100 cm of snow from the past week is rapidly settling, but some storm slab instabilities may still be present, especially in wind-affected areas.

A weak layer composed of facets on a crust is buried 150 to 250 cm deep and remains sensitive to both human and natural triggers. The snowpack below this interface strong and bonded.

Weather Summary

Wednesday Night

Clearing skies. 25 km/h northeast ridgetop wind. Treeline temperature -4 °C.

Thursday

Mostly sunny. 25 km/h northwest ridgetop wind. Treeline temperature +3 °C with freezing level climbing to 3000 m by midday.

Friday

Mostly sunny. 15 km/h north wind. Treeline temperature +6 °C with freezing level climbing to 3300 m.

Saturday

Sunny. 45 km/h southeast ridgetop wind. Treeline temperature +8 °C with freezing level sustained at 3300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid avalanche terrain during periods of strong sun.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
Cornice failure may trigger large avalanches.

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.

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.