Avalanche Forecast

Archived

Feb 9th, 2025–Feb 10th, 2025

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Purcells, Esplanade, Dogtooth, East Purcell.

Look for areas where the surface snow is soft and avoid areas where it feels dense or "slabby".

Heavy triggers, like icefall, an avalanche or a cornice could produce large natural avalanches.

Confidence

High

Avalanche Summary

Saturday: A few small (size 1) rider triggered loose natural avalanches and one large (size 2) natural wind slab on north and east aspects were reported.
Friday: A small natural wind slab was was reported on a northeast aspect in the alpine and a large natural (size 2.5 was reported) starting as icefall on a northwest aspect in the alpine.
Thursday: A few small wind slab avalanches on north and east aspects were reported.

Snowpack Summary

25-45 cm of soft surface snow is faceting in sheltered terrain at treeline and below. This covers a layer of surface hoar buried in late January that may be as large as 15 mm in some places. The surface hoar sits on loose, faceted snow in shaded terrain, and a crust on steep slopes facing the sun.

In the alpine, exposed terrain is generally wind-affected, and there is likely no surface hoar included in the late January layer, just facets, old wind-affected surfaces, or a sun crust.

A weak layer of facets from early December is 60 to 120 cm deep.

The base of the snowpack consists of a thick crust with facets or depth hoar in many areas.

Weather Summary

Sunday Night

Mostly clear. 10 to 20 km/h north ridgetop wind. Treeline temperature -24 °C.

Monday

Mostly sunny. 10 to 20 km/h north ridgetop wind. Treeline temperature -18 °C.

Tuesday

Mostly sunny. 10 to 40 km/h northwest ridgetop wind. Treeline temperature -18 °C.

Wednesday

Mostly sunny. 10 to 30 km/h northwest ridgetop wind. Treeline temperature -15 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be aware of the potential for remote triggering and large avalanches due to buried surface hoar.
Keep in mind that human triggering may persist as natural avalanches taper off.
Be especially cautious as you transition into wind-affected terrain.
Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.

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.