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Avalanche Forecast

Archived

Feb 19th, 2025–Feb 22nd, 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

Waterton Lakes, Waterton.

The persistent slab problem may be becoming active as the snowpack warms up. Windslabs may be able to trigger a larger persistent slab, however we have limited data and a lot of uncertainty around this problem. Exercise caution in wind affected and thin rocky terrain.

Confidence

Moderate

Avalanche Summary

On Wednesday, a few natural windslabs in steep slopes below cliffs were observed, and one natural size 2 slab avalanche which we suspect was a persistent slab. Numerous dry loose avalanches to size 2 were observed on steep slopes Monday and Tuesday.

Snowpack Summary

20-30 cm storm snow is being redistributed into windslabs in the alpine and at treeline. These are sitting over storm snow and older windslabs. The January drought layer is 30 - 60 cm down. This layer includes facetted snow on northerly aspects or a melt freeze crust below treeline and on steep solar slopes into the alpine. Generally, the snowpack has become weak and facetted.

Snowpack depths at treeline range from 100 - 160 cm.

Weather Summary

A continued warming trend with increased wind over the next few days.

Check out the Mountain Weather Forecast for the most up to date information.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.

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.