Avalanche Forecast

Archived

Mar 10th, 2024–Mar 11th, 2024

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 possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Purcells, Dogtooth, East Purcell.

Don't let your guard down as snowfall begins. Buried weak layers remain likely to trigger.

Avoid exposing yourself to large slopes or avalanche paths.

Confidence

Moderate

Avalanche Summary

Over the last 3 days natural avalanche activity appears to be decreasing, but human triggering continues. Slabs have been triggered by riders including remote triggers from up to 100 m away, indicating weak layers remain sensitive.

Persistent slab avalanches have been reported to size 3.5 this week. If triggered a large and destructive avalanche remains likely as shown by this remotely triggered avalanche near Golden on Thursday.

Snowpack Summary

Light accumulations of storm snow will fall over sun crusts on south facing slopes, lightly wind-affected snow at higher elevations, and settling snow elsewhere.

A widespread crust is roughly 80-120 cm deep. Weak faceted crystals and surface hoar above this crust are contributing to large avalanches across the province and continue to be the primary layer of concern here.

Additionally, the lower snowpack is mostly made up of weak and faceted layers.

Weather Summary

Sunday Night

Mostly cloudy with 5-15 cm of snow. 20-40 km/h southwest ridgetop wind. Freezing levels drop to 1000 m.

Monday

Mostly cloudy with possible flurries. 20-30 km/h southwest ridgetop wind. Freezing levels rise to 1700 m by the afternoon. Treeline temperature -3 °C.

Tuesday

Mostly cloudy. 10-20 km/h southwest ridgetop wind. Freezing levels rise to 1800 m. Treeline temperature -2 °C.

Wednesday

A mix of sun and cloud 10-20 km/h northwest ridgetop wind. Freezing levels rise to 1700 m Treeline temperature -3 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Conservative terrain selection is critical, choose only well supported, low consequence lines.
Remote triggering is a concern, watch out for adjacent and overhead slopes.
Be aware of the potential for large, destructive avalanches due to the presence of deeply buried weak layers.

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.