Avalanche Forecast

Archived

Jan 12th, 2024–Jan 13th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

South Coast Inland, Birkenhead, Duffey, South Chilcotin, Stein, Taseko.

Wind effected storm snow still needs time to settle and bond with old surfaces, which takes extra time in the cold.

Factor cold temperatures and wind chill in your trip plan this weekend.

Confidence

Moderate

Avalanche Summary

Size 2 slab avalanches were reported on north and east facing slopes during Tuesday's storm. Reactivity is expected to continue in wind loaded features.

On Wednesday a size 2.5 naturally triggered persistent slab was reported on a northwest facing slope in the alpine, which had reloaded from a previous recent avalanche.

Last Saturday, a very large avalanche was reported on Joffre shoulder, suspected to have failed on the weak layer of facets or surface hoar over a crust.

Snowpack Summary

Up to 50 cm of available snow is being redistributed into wind slabs on south facing slopes from these arctic winds. Slabs overly wind affected surfaces in most areas.

A crust is found at treeline and below, 40-80 cm down. In some areas, a layer of preserved surface hoar is found above the crust.

Another weak layer of facets or surface hoar overlying a crust is found at the base of the snowpack down 80 to 120 cm. This is the suspected failure plane for large avalanches in the region that occurred on January 6.

Snowpack depths are 100 to 140 cm at treeline and decrease rapidly below.

Weather Summary

Friday Night

Clear skies with northerly winds 10-30 km/h. Treeline temperature remains steady around -30 °C.

Saturday

Sunny with northerly winds 10-30 km/h. Treeline temperatures rise to -20 °C.

Sunday

Sunny with northerly winds 20-40 km/h. Treeline temperatures rise to -17 °C.

Monday

Sunny with northerly winds 20-40 km/h. Treeline temperatures rise to -13 °C.

With unusually cold temperatures forecast for this weekend, check out the most recent Forecaster Blog for tips on backcountry preparedness.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Expect slab conditions to change drastically as you move into wind exposed terrain.
Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.

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.