Avalanche Forecast

Issued: Feb 22nd, 2017 4:45PM

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

Avalanche Canada cgarritty, Avalanche Canada

Wind slabs at upper elevations remain a concern. Don't let the improving conditions tempt you into unsupported terrain.

Summary

Confidence

Moderate -

Weather Forecast

Thursday: A mix of sun and cloud. Winds light from the northwest. Freezing level around 700 metres with alpine temperatures of -9 in the north of the region, closer to -5 in the south. Friday: Cloudy with sunny periods and isolated flurries bringing a trace of new snow. Winds light from the northeast. Freezing level around 700 metres with alpine temperatures of -10 in the north of the region, closer to -6 in the south. Saturday: Cloudy with sunny periods and isolated flurries bringing a trace of new snow. Winds moderate from the southwest. Freezing level around 700 metres with alpine temperatures of 10 in the north of the region, closer to -6 in the south.

Avalanche Summary

Ski cutting continued to produce Size 1 wind slab releases in the region on Tuesday. As on Monday, natural sluffing was again observed from steep sun exposed slopes, with deposits reaching up to Size 1.5. A natural cornice failure also triggered a Size 2.5 wind slab in the Pemberton Icefield area, immediately adjacent to the northern part of the South Coast Inland region. Several other natural cornice releases to Size 2 were also observed on north aspects in the alpine, however these failed to trigger slabs below.Although the report is older, a Size 3 persistent slab avalanche was observed up the Hurley at treeline elevation on Friday. It likely failed on the weak layer from early February.For Thursday, lingering wind slabs are the main concern. Look for these in immediately leeward features on northerly aspects in exposed terrain.

Snowpack Summary

At higher elevations, 10-30 cm of recent snow overlies the widespread mid-February crust layer. Recent reports suggest this snow is well bonded to the crust. Recent cornice and wind slab releases have been reported in high north facing alpine terrain, but both cornices and wind slabs are expected to have gained considerable strength over the past couple days of colder temperatures. The potential for human triggering wind slabs will remain a concern over the short term. In the north of the region, a facet/surface hoar layer from early February down 60-100 cm was recently reactive in snowpack tests but would be very difficult to trigger without something heavy like a cornice fall or smaller avalanche stepping down. In the south of the region, the mid and lower snowpack are well settled and strong.

Problems

Wind Slabs

An icon showing Wind Slabs
Maintain caution around wind slabs in wind-exposed, higher elevation terrain. These are likely to remain sensitive to human triggering over the short term.
Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.Avoid areas where the surface snow feels stiff or slabby.

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

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

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