Avalanche Forecast

Archived

Jan 29th, 2024–Jan 30th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Kootenay, Field.

A widespread avalanche cycle was observed Monday with numerous avalanches up to size 2.5, having occurred today near highway 93N. Freezing levels will peak late tonight, raising the avalanche danger to high at all elevations into Tuesday. Avoid avalanche terrain.

Confidence

Moderate

Avalanche Summary

A widespread cycle was observed on Mt Dennis and Mt Stephen on Monday with slides up to size 2.5. They were a mix of slabs and loose wet avalanches. This cycle is expected to continue into Tuesday with warm temperatures and high freezing levels.

Snowpack Summary

Rain has saturated the snowpack up to 1900 meters and wind has created windslabs in most alpine/treeline areas. These slabs are releasing on two weak layers in the upper snowpack: 1) facets from the cold snap 10-30cm deep, and 2) surface hoar or sun crust below the facets 30-50cm deep. The lower snowpack is comprised of weak facets and depth hoar. Overall this is a weak snowpack that is untrustworthy.

Weather Summary

The next pulse of moisture comes through on Tuesday although not much precipitation is expected, less than 3 cm. Freezing levels fall slightly over all areas to a range of 2100-2400 m. Ridgetop winds remain strong to extreme from the southwest.

Tuesday evening as the winds taper and temperatures cool off, there is the potential for an inversion to set up Wednesday.

Click here for more info on Mountain Weather.

Terrain and Travel Advice

Avoid areas where the snow feels stiff and/or slabby.
The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.