Avalanche Forecast

Issued: Feb 22nd, 2017 4:11PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada mgrist, Avalanche Canada

The best riding right now is probably on high north aspects, which is also where the hazard is the highest. Don't let your guard down when searching for fresh powder.If the sun comes out in full force, use extra caution on south slopes.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

We're into a stable and benign weather pattern with cooling temperatures and isolated flurries.THURSDAY: Cloudy with sunny breaks and isolated flurries / Light variable winds / Freezing levels at valley bottom / Alpine high temperatures near -7 Celsius.FRIDAY: A mix of sun and cloud and isolated flurries / Light variable winds / Freezing levels at valley bottom / Alpine high temperatures near -8 Celsius.SATURDAY: Cloudy with light flurries in the afternoon (local accumulations 5-10cm possible) / Light southwest winds / Freezing levels at valley bottom / Alpine high temperatures near -7 Celsius.

Avalanche Summary

On Tuesday ski tourers near Kimberley remote-triggered a Size 2 wind slab on a southeast aspect near 2600m.On Monday afternoon we had three spooky large avalanches: one natural and two triggered by humans:1) A Size 2.5 persistent slab (40-75cm thick) near Golden was triggered by a skier on a northeast aspect near 2300m. See here for this great MIN post.2) A Size 3 persistent slab (50-120cm thick) near Golden was remote triggered by a touring party on a southeast aspect near 2300m.3) A Size 2.5 persistent slab (30cm thick) near Invermere ran naturally on a north aspect near 2600m.Storm slabs from recent snowfall remain sensitive to light triggers and have the potential to step down and trigger persistent slab avalanches.

Snowpack Summary

We've had minor snowfall amounts (10-25cm) over the past several days (and some higher amounts in the south) with moderate southerly winds in some locations. Expect to find 25-40 cm of more recent snow bonding slowly to buried Feb 15th surface hoar and/or a sun crust, and blown into wind slabs at higher elevations. Storm snow from previous weeks is still bonding poorly to the Feb 3rd surface hoar / sun crust layer, which is now down 60-80 cm.At 2000m and below a (supportive) melt-freeze crust can be found on almost all elevations and aspects. The sun is starting to pack a punch and can trigger loose snow avalanches mid-day. The sun is also creating a thin crust on steep southerly aspects.A persistent weakness buried mid January is now down 80-150 cm and the November crust is down around 180 cm. These deep persistent weaknesses still have the potential to wake up and become reactive with human triggers. (See MIN post above).

Problems

Storm Slabs

An icon showing Storm Slabs
The fresh snow is sensitive to light triggers and particularly deep and touchy on wind-loaded slopes.
Be alert to conditions that change with elevation.Avoid freshly wind loaded features.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
A persistent weakness down 60-80 cm remains sensitive to light triggers in isolated areas. Smaller avalanches have the potential to step down to this and deeper persistent weakness resulting very large avalanches.
Be aware of the potential for large avalanches due to the presence of deeply buried weak layers.Whumpfing, shooting cracks and recent avalanches are all strong indicators of unstable snowpack.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 4

Valid until: Feb 23rd, 2017 2:00PM

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