Avalanche Forecast

Archived

Feb 15th, 2024–Feb 16th, 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

North Columbia, South Columbia, Blue River, Clearwater, Esplanade, Jordan, North Monashee, North Selkirk, Shuswap, West Purcell, Badshot-Battle, Central Selkirk, Goat, Gold, Kokanee, North Okanagan, Retallack, Valhalla, Whatshan.

Start on small slopes, and downgrade your objective if you find signs of instability like shooting cracks or whumpfs.

Touchy slabs have been surprising backcountry users.

Confidence

Moderate

Avalanche Summary

On Wednesday, several rider-triggered slab avalanches continued to be reported on all aspects at treeline and above, up to size 2.

On Tuesday, numerous similar avalanches were reported up to size 2.5.

Some of these avalanches are failing on buried sun crust and surface hoar 20-25 cm below the snow surface, and others are failing on a firm crust 30-50 cm deep.

Many of these avalanches surprised people with wider than expected propagation and remote triggering from afar.

Snowpack Summary

A sun crust likely exists on steep south facing aspects. 15 to 25 cm of snow overlies a variety of surfaces including a weak layer of small surface hoar in sheltered areas and/or another thin sun crust on solar aspects.

The widespread crust buried in early February is down 30 to 50 cm and is proving to be touchy to human and machine triggers. In most places this crust is widespread up to 2400 m.

Various weak layers persist in the mid to lower snowpack, however, triggering these layers is unlikely where they are bridged by a thick crust.

Weather Summary

Thursday Night

Clear. No new snow expected. Light northeast ridgetop wind. Treeline temperature around -10 °C.

Friday

Sunny. No new snow expected. Light east or northeast ridgetop wind. Treeline temperature around -6 °C.

Saturday

Sunny. No new snow expected. Light to moderate southeast ridgetop wind. Treeline temperature around -4 °C.

Sunday

Mostly cloudy. No new snow expected. Light southeast ridgetop wind. Treeline temperature around -3 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Choose slopes that are well supported and have limited consequence.
A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.

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.

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.