Avalanche Forecast

Archived

Feb 7th, 2025–Feb 8th, 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 unlikely, human triggered possible.

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

Lizard-Flathead, South Rockies, Flathead, Lizard, Bull, Elkford West.

A weak layer of snow is buried 50 to 70 cm deep and is still producing natural avalanches.

Avoid areas where the surface snow is denser and feels "slabby"

Confidence

Moderate

Avalanche Summary

Thursday: A few large (size 2 to 2.5) natural avalanches were reported on a southeast and east aspects in the alpine.
Wednesday: A few small (size 1) natural and rider triggered avalanches were reported in the recent storm snow.

A weak layer of snow formed during the cold drought period in January is continuing to produce large natural avalanches in the region. Small wind slab avalanches are being triggered in wind loaded features at all elevations.

Snowpack Summary

35 to 50 cm of soft snow is on the surface, with deeper deposits in wind-loaded areas. Cold temperatures have kept the recent storm snow loose and low density.

Variable wind speeds and directions through the storm and after mean that the extent of wind-affected snow at different aspects and elevations will vary across the region.

This recent snow has not bonded well to the late January drought layer, which includes melt-freeze crusts on sun-exposed slopes, large surface hoar or facets in sheltered areas, and wind-affected snow in exposed terrain at ridgelines.

The lower snowpack is strong and bonded.

Weather Summary

Friday Night

Clear. 10 to 40 km/h west ridgetop wind. Treeline temperature -20 °C.

Saturday

Partly cloudy. 20 to 40 km/h west ridgetop wind. Treeline temperature -13 °C.

Sunday

Partly cloudy. 10 to 30 km/h west ridgetop wind. Treeline temperature -15 °C.

Monday

Mostly sunny. 10 to 20 km/h northeast ridgetop wind. Treeline temperature -20 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Use small, low consequence slopes to test the bond of the new snow.
Keep in mind that human triggering may persist as natural avalanches taper off.
Be careful as you transition into wind-affected terrain.
Recent wind has varied in direction, so watch for wind slabs on all aspects.

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.