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 17th, 2023–Mar 18th, 2023

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

Regions

Northwest Coastal, Kitimat, Nass, Rupert, Seven Sisters, Shames, Stewart, Howson.

Storm snow sits over surface hoar which remains reactive to human triggers. Watch for deeper deposits in wind loaded terrain. Stick to conservative terrain and be alert for signs of instability.

Monitor snow conditions on sun baked slopes, avalanches become more likely in the afternoon as daytime temperatures rise and sun effect increases.

Confidence

Moderate

Avalanche Summary

On Thursday natural slab avalanches were observed to size 2, and skier triggered avalanches were observed to size 1. Most avalanches were thought to occur on the buried surface hoar layer, with greater reactivity in wind loaded features. Explosive control work triggered cornice falls that produced slab avalanches to size 2.5 on the slopes below.

Loose wet avalanches were reported to size 1.5 from steep sun affected terrain.

The primary concern is the new snow that overlies surface hoar and/or hard interfaces. As the snow further settles and forms a slab, it is expected to become more reactive. A warming trend with sunny skies could rapidly form slab properties within the storm snow.

Snowpack Summary

30 to 40 cm of storm snow overlies large, weak surface hoar crystals in shaded and wind-sheltered terrain, wind affected snow in wind-exposed terrain, and a hard melt-freeze crust on sun-exposed slopes. Southwest winds have created deeper and more reactive deposits on north to east facing terrain features near ridges. Warmer weather and sunny skies may moisten the snow surface on sun-exposed slopes and at low elevations, which may refreeze into a melt freeze crust overnight.

Another layer of surface hoar and/or weak faceted grains may be found about 60 cm deep, particularly on shaded aspects near treeline.

The remainder of the snowpack is consolidated and strong.

Weather Summary

Friday Night

Partly cloudy with moderate southerly winds. Freezing levels drop to valley bottom for most areas, but remain elevated around 1200 m overnight for the immediate coast.

Saturday

Mostly sunny with increasing afternoon cloud. Freezing levels rise to 1400 m, alpine high temperatures of -3 °C.

Sunday

Cloudy with snowfall beginning early morning, 5-15 cm over the day. Moderate southeast winds. Freezing levels reach 1200 m.

Monday

Cloudy with moderate easterly winds. Light snowfall continues. Freezing levels remain around 1000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

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.

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.