Avalanche Forecast

Archived

Mar 31st, 2023–Apr 1st, 2023

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

Cariboos, McBride, Premier, Quesnel, Sugarbowl, Renshaw, Robson.

Make conservative terrain choices while we see how the snowpack reacts to the storm. New snow and wind are making wind slab avalanches possible.

Confidence

Moderate

Avalanche Summary

On Thursday, south of Valemount, several small (size 1.5) naturally triggered avalanches were reported on SE-SW aspects in the alpine. They occurred on slopes facing the sun during the warmest part of the day.

On Wednesday, west of McBride, a large (size 3.0), naturally triggered, cornice avalanche was reported on a north aspect in the alpine. It travelled 600 m down the slope and entrained a large amount of loose snow.

Snowpack Summary

Up to 10cm of soft snow sits over a thin crust on steep slopes facing the sun right up into the alpine. Snow that fell earlier in the week has been redistributed by northeast winds. On high, north-facing terrain, wind slabs may sit over facets and surface hoar.

The mid-snowpack is generally strong. There continues to be a weak layer of facets from November at the base of the snowpack. This layer remains a concern in rocky, shallow, or thin to thick snowpack areas at treeline and above.

Weather Summary

Friday Night

Mostly cloudy. 0-5 cm of snow expected. Light southwest ridgetop wind, trending to moderate at higher elevations. Freezing level at valley bottom. Treeline high around -5°C.

Saturday

Partly cloudy. 5-10cm of snow expected. Light southwest ridgetop wind, trending to moderate west at higher elevations. Wind may die off mid-day, and pick back up from the northwest in the afternoon. Freezing level rising to 1200 m. Treeline high around -5°C.

Sunday

Mostly cloudy. 0-2 cm of snow expected. Light variable wind. Freezing level at valley bottom in the morning, rising to 1200 m.

Monday

Partly cloudy. 0-2 cm of snow expected. Light northwest wind. Freezing level at valley bottom in the morning, rising to 1300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Expect slab conditions to change drastically as you move into wind exposed terrain.
Stay off recently wind loaded slopes until they have had a chance to stabilize.
Closely monitor how the new snow is bonding to the crust.
Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.

Problems

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.