Avalanche Forecast

Archived

Mar 3rd, 2023–Mar 4th, 2023

Alpine

Natural avalanches possible, human triggered probable.

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 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.

Regions

Coquihalla, Harrison-Fraser, Manning, Skagit.

Storm slabs will remain reactive until the snow has time to settle.

Seek out low-angle sheltered areas for the best riding.

Confidence

Moderate

Avalanche Summary

Considering the amount of snow that our region has received over the last few days, it should be no surprise that there has been a widespread avalanche cycle. These have been in the form of storm and wind slabs and have reached up to size three.

If you venture out this weekend expect this trend to continue.

Snowpack Summary

Up to 80 cm have fallen over the last few days. Temperatures remain cool so much of this snow will take some time to settle. Southerly winds redistributed this new snow at higher elevations in exposed areas creating reactive wind slabs. The new snow may have a poor bond to the underlying stiff wind slabs and faceted snow formed by recent cold temperatures.

A melt-freeze crust formed in mid-January is buried up to 200 to 250 cm deep. It is still a concern but it seems to be gaining strength. The snow below this layer is well consolidated.

Weather Summary

Friday Night

Cloudy, 5 to 10 cm accumulation, winds southwest 20 km/h switching to the southeast by morning, treeline temperatures -10 to -5 °C.

Saturday

Mostly cloudy with sunny breaks, 4 cm accumulation in the northwest areas, winds southeast 20 to 30 km/h gusting to 50, treeline temperatures -6 °C, and freezing level to 1000 m.

Sunday

Mostly cloudy, up to 5 cm accumulation, winds southeast 15 km/h, treeline temperatures -10 to -5 °C, and freeing levels up to 1000 m.

Monday

Cloudy with sunny periods, trace accumulation, winds south southeast 10 km/h, treeline temperatures -8 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for changing conditions today, storm slabs may become increasingly reactive.
Closely monitor how the new snow is bonding to the crust.
Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

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.

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.