Avalanche Forecast

Archived

Mar 7th, 2024–Mar 8th, 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 and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

Avoid being in or under avalanche terrain.

New snow and wind are creating a new avalanche problem, and increasing the chance of triggering deeper weak layers.

Confidence

Moderate

Avalanche Summary

On Tuesday and Wednesday, large (up to size 2) natural and human-triggered avalanches continued to occur.

Some reports are of remotely triggered avalanches, which indicate a sensitive snowpack and the need for conservative terrain choices, especially with increased load from new snow and wind.

Click on the photos below for more details.

Snowpack Summary

Storm totals should reach 20-50 cm by the end of the day on Friday. Strong to extreme south winds could scour ridgetops and create deeper, more reactive deposits in leeward terrain, possibly even further downslope than expected.

Several persistent weak layers are likely buried between 70 and 140 cm deep. These weak layers include hard crusts, weak facets and surface hoar. Avalanches continue to be caused on these layers, including remote triggering and very large step-down avalanches.

Weather Summary

Thursday Night

Mostly cloudy. 10 to 15 cm of snow expected to valley bottom, up to 35 cm around Kitimat. Strong to extreme south wind. Treeline temperature around -4 °C.

Friday

Cloudy. 5 to 15 cm of snow expected to near valley bottom. Closer to 20 cm around Kitimat. Strong southwest wind in the morning decreasing to moderate in the afternoon. Treeline temperature around -5 °C.

Saturday

Mostly cloudy. 1 to 3 cm of snow expected above 500 m. Light variable ridgetop wind. Treeline temperature around -5 °C.

Sunday

Mostly cloudy, possibly a bit clearer east of Terrace. 1 to 3 cm of snow expected above 750 m. Light to moderate south or southeast wind. Treeline temperature around -4 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Remote triggering is a big concern, be aware of the potential for wide propagations and large, destructive avalanches at all elevations.
Caution required around non obvious avalanche terrain like road cutbanks, cutblocks and other non obvious avalanche terrain
Storm slab size and sensitivity to triggering will likely increase through the day.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Problems

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.

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.