Avalanche Forecast

Archived

Feb 28th, 2025–Mar 1st, 2025

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 unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

North Rockies, Sugarbowl, East Kakwa, Kakwa, McGregor, Pine Pass, Renshaw, Robson, Tumbler.

Recent avalanche activity indicates an unstable snowpack & remote-triggering remains a serious concern.

Stick to conservative terrain and practice good travel habits.

Confidence

High

Avalanche Summary

In the past few days, many natural and rider-triggered wind slab and persistent slab avalanches have been reported, up to size 2.5. These avalanches have mainly occurred in north-to-east facing alpine and treeline terrain.

Similar activity is expected on Saturday with continued wind, warming, and precipitation.

Snowpack Summary

10 to 20 cm of new snow on Thursday, accompanied by strong southwest alpine winds built fresh wind slabs in the alpine and treeline. In many areas the new snow was wet or fell as rain, creating a moist surface or crust.

Below the new snow, 20 to 50 cm of settling storm snow from earlier in the week is sitting on a weak layer of surface hoar or facets in many areas. Additional persistent weak layers are buried between 60 to 90 cm. These consist of more surface hoar and faceted grains, and/or a hard crust. These persistent layers continue to be a source of concern and have the potential for large step-down avalanches.

Weather Summary

Friday Night

Partially cloudy. 30 to 50 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1500 m.

Saturday

Mostly cloudy with up to 5 mm of precipitation. 30 to 60 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1500 m.

Sunday

A mix of sun and cloud with light precipitation. 15 to 40 km/h northwest ridgetop wind. Treeline temperature -2 °C. Freezing level drops to 1000 m.

Monday

A mix of sun and cloud. 10 to 30 km/h southwest ridgetop wind. Treeline temperature -4 °C. Freezing level 1300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Remote triggering is a concern; avoid terrain where triggering overhead slopes is possible.
Stay away from steep slopes, open slopes, and convex rolls at and below treeline where weak layers may be preserved.
Be especially cautious as you transition into wind-affected terrain.
Use small, low consequence slopes to test the bond of the new snow.

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.

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.