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

Mar 16th, 2023–Mar 17th, 2023

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 unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

North Columbia, South Columbia, Esplanade, Jordan, North Selkirk, Shuswap, Badshot-Battle, Central Selkirk, Goat, Gold, Kokanee, North Okanagan, Retallack, Valhalla, Whatshan.

Expect avalanche hazard to be at its highest during the warmest part of the day.

Avoid solar slopes in the afternoon especially if they contain overhead hazards.

Confidence

Moderate

Avalanche Summary

Wednesday's avalanches were a mixed bag that included storm slabs, wind slabs, cornices, and deep persistent slabs. A few that caught people by surprise were triggered accidentally by riders and vehicles, some of which were set off remotely. They were found on all aspects and the wind and storm slabs were triggered up to 50 cm deep on the March 11th layer that the most recent storm snow covered up.

Explosives were used to trigger the cornice avalanches, most of which were size two. The load that these falling cornices placed on the snowpack below did not trigger buried weak layers. However, a natural size 3.5 avalanche was triggered and it ran on the deep persistent layer, buried 100 cm, from November. This is a good reminder that solar input can "wake up" these deeper layers.

Snowpack Summary

A storm slab, 40 to 60 cm, overlies a variety of surfaces, which include surface hoar, 3 to 10 mm, on shady slopes at all elevations, wind-affected surfaces at treeline and above, and sun crust on sunny aspects. Moderate to strong southerly winds that accompanied this snow may have created wind slabs at higher elevations. Solar aspects and lower elevations will be affected by day time warmer and nighttime freezing. Expect a crust in the morning and moist snow in the afternoon.

The mid-snowpack is generally strong but the lower snowpack is a different story.

The November facets are still prominent at the base of the snowpack. They are showing signs of improving but this layer remains a significant concern in rocky, shallow, or thin to thick snowpack areas at treeline and above.

Weather Summary

Thursday Night

Clear, no accumulation, winds southeast 10 to 15 km/h, treeline temperatures -5 °C with freezing levels dipping to 1200 m.

Friday

Sunny, no accumulation, winds southeast 10 to 15 km/h, treeline temperatures -5 to 0 °C with freezing levels getting up to 1800 m.

Saturday

Mostly sunny, no accumulation, winds southeast 10 to 15 km/h, treeline temperatures -5 to 0 °C with freezing levels getting up to 1800 m.

Sunday

A mix of sun and cloud, no accumulation, winds southerly 10 to 15 km/h, freezing levels to 1900 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Don't let the desire for deep powder pull you into high consequence terrain.
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Be carefull around freshly wind loaded features.

Problems

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.

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.