Avalanche Forecast

Archived

Jan 1st, 2024–Jan 2nd, 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

Sea To Sky, Brandywine, Garibaldi, Homathko, Spearhead, Tantalus, Sky Pilot, Birkenhead.

Choose slopes that are sheltered from the wind, and avoid, shallow, rocky alpine slopes.

Where wind slabs sit on a buried weak layer, large avalanches are more likely.

Confidence

Moderate

Avalanche Summary

On Sunday, northwest of Pemberton, a large (size 2) skier remote avalanche was reported on a north aspect in rocky alpine terrain. This problem seems to be most active in this general area, but due to it's low-likelihood/high consequence nature, we remain wary of the rest of the forecast area.

On Friday, very large persistent slabs (up to size 3), 100-120 cm deep, were naturally triggered on Decker Mountain and Panorama Ridge in Whistler, on rocky alpine northern slopes.

Snowpack Summary

15-25 cm of recent snow may be found over a thin frozen crust up to 2000 m.

Underneath, a mix of soft snow and heavily wind-affected snow overlies a layer of poorly bonded crusts and surface hoar. These have shown sensitivity to natural and remote triggers over the last 3 days. The lower snowpack is strong and bonded.

The snowpack at treeline has been rain-saturated, and a surface crust may form soon with upcoming cooling. Total snow depths remain below average, with 60 to 80 cm at treeline.

Weather Summary

Monday Night

Increasing cloud through the night. No snow/rain expected. Light south or southeast ridgetop wind, treeline temperature around -2 °C, freezing level 1100-1400 m.

Tuesday

Cloudy. 5-7 cm of snow above 1000 m. Light to moderate southeast ridgetop wind. Treeline temperature around -1 °C.

Wednesday

Cloudy. Isolated flurries above 1200 m. Light southwest ridgetop wind. treeline temperature around -2 ° C.

Thursday

Cloudy. 10 cm of snow expected above 750 m. Light to moderate south or southwest ridgetop wind. Treeline temperature around -3 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.
In times of uncertainty conservative terrain choices are our best defense.
Carefully evaluate steep lines for wind slabs.

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.