Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Apr 26th, 2023–Apr 27th, 2023

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Below Threshold.
Alpine
Natural and human triggered avalanches likely.
Treeline
Natural and human triggered avalanches likely.
Below Treeline
Below Threshold.
Alpine
Natural and human triggered avalanches likely.
Treeline
Natural and human triggered avalanches likely.
Below Treeline
Natural and human triggered avalanches likely.

Regions

Banff Yoho Kootenay, Banff, East Side 93N, Kootenay, Lake Louise, LLSA, Sunshine, West Side 93N, Field.

We expect rising hazard throughout the day Thursday due to solar input. The deep persistent layer is still a major concern and should become more active in the coming days. Starting Friday, we will see 3000-3500m freezing levels and likely a large avalanche cycle.

Confidence

Moderate

Avalanche Summary

A couple of loose wet avalanches in very steep, East facing terrain today in the Sunshine Village backcountry, but no other avalanches were observed or reported Wednesday.

Snowpack Summary

Thick crusts on all aspects werent breaking down today over 2000m. In general, solar aspects are getting moist in the afternoon, creating new crusts daily, and multiple buried crusts are present. On northerly aspects, temperature crusts are present up to 2200m (maybe higher), with 10-20 cm of preserved surface snow above this elevation. The base of the snowpack remains weak due to the presence of facets and depth hoar.

Weather Summary

Around 5cm of snow Wednesday night with freezing levels near valley bottom.

Thursday: Clearing skies and 2500m freezing levels, NW winds 40km. Overnight Thursday freezing levels to valley bottom, but temperatures will be inverted at 2000m with warmer air above.

Friday: NW winds, mainly clear skies. Freezing levels will spike to 3000-3500m.

Terrain and Travel Advice

  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

Problems

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.

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.

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.