Avalanche Forecast

Archived

Apr 8th, 2023–Apr 9th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Purcells, Dogtooth, East Purcell.

Continue to use good travel habits, and use extra caution around thin, rocky start zones.

Carefully choose the terrain you play in. A weak, unpredictable layer continues to lurk near the bottom of the snowpack.

Confidence

Moderate

Avalanche Summary

On Saturday, near both Golden and Invermere. Several small (size 1-1.5), naturally triggered loose wet avalanches were reported on steep slopes. Sun and/or warm temperatures were the most likely triggers.

On Thursday, north of Golden, just outside of the forecast area, a large (size 2), rider triggered, deep persistent slab avalanche was reported on a northwest aspect in the alpine. The avalanche started 50 m above the riders, and 2 sympathetic avalanches were observed on the adjacent slope. See the excellent Mountain Information Network (MIN) post here for more information, including photos, and reflections on a close call.

Snowpack Summary

Dry, powder snow remains on shaded (northerly) slopes in the alpine. Moist snow or thin crusts exist on solar aspects at all elevations, and on all aspects below treeline.

The mid-snowpack may still contain a number of weak layers, primarily in sheltered treeline terrain. No recent avalanche activity has occurred on these layers suggesting they are likely not a primary concern.

The lower snowpack includes a widespread layer of large, weak facets and/or depth hoar crystals. This weak layer has been responsible for several very large and destructive avalanches throughout the season, including one on Thursday.

Weather Summary

Saturday Night

Mostly clear. Trace of snow expected. Snow line around 1200 m. Treeline temperature around -2°C. Light southwest ridgetop wind, trending to strong at higher elevations.

Sunday

Mostly cloudy, possibly sunny in the afternoon. Trace of snow expected in the alpine. Rain below 1800 m. Treeline temperature around 0°C. Light southwest ridgetop wind, trending to strong at higher elevations.

Monday

Mostly cloudy. 8-15 cm of snow expected in the alpine. Rain below 1900 m. Light variable ridgetop wind, strong southwest at high elevations.

Tuesday

Partly cloudy. 5-10 cm of snow expected as the snow line drops back to valley bottom. Light southwest ridgetop wind, trending to moderate at high elevations.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Carefully evaluate bigger terrain features on an individual basis before committing to them.

Problems

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.