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

Dec 29th, 2023–Dec 30th, 2023

Alpine
Natural and human triggered avalanches likely.
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 possible, human triggered probable.
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

Kitimat, Nass, Rupert, Seven Sisters, Shames.

6:45 AM Update: Warm, stormy weather has increased the likelihood of triggering large, destructive avalanches.

Confidence

Moderate

Avalanche Summary

On Friday a MIN post described seeing several natural avalanches near the Anderson Cabin. Thursday a vehicle triggered a large avalanche in the alpine. It was reported to have failed 1 m deep on a layer of surface hoar. Wednesday two small rider-triggered avalanches and one large (size 2.5) naturally occurring slab were reported near Shames. With rain and warm temperatures in the forecast, we expect to see a spike in avalanche occurrences.

Snowpack Summary

Around 20 mm of rain is expected to saturate and overload the snowpack. 30-45 cm of heavy storm snow has bonded poorly to a slippery rain crust formed on Christmas. At upper elevations, strong winds from variable directions have likely built reactive slabs on many aspects in open areas and near ridge crests.Two buried surface hoar layers can still be found in isolated areas, buried 75-100 cm, and 120-200 cm deep. The remaining mid and lower snowpack contains several well-bonded crusts. Snow depths are highly variable depending on elevation, and decrease rapidly below treeline.

Weather Summary

Friday Night

Cloudy, moderate rain 5-8 mm is expected to mountain top, with the freezing level between 1800-2000 m. 30-50 km/h southerly winds and treeline temperatures around 2 °C.

Saturday

Cloudy, moderate to heavy rain 5-15 mm or 5-15 cm snow above 1500m. 20-35 km/h easterly winds, freezing levels between 1800-1400 m, and a high of 2 °C at treeline.

Sunday

Cloudy with no precipitation, 10-25 km/h southerly winds, freezing level dropping to 400 m, and high of -2 °C at treeline.

Monday

Cloudy with 3 cm of new snow, 10 km/h easterly winds, freezing level around 600 m, and a high of -2 °C at treeline.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Travel in alpine terrain is not recommended.
  • Only the most simple non-avalanche terrain free of overhead hazard is appropriate at this time.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.
  • Avoid avalanche terrain during periods of heavy rain.

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.

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.