Avalanche Forecast

Issued: Mar 6th, 2016 8:00AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Wind Slabs, Persistent Slabs and Cornices.

Parks Canada percy woods, Parks Canada

Conservative route selection, group management and terrain use are needed today given the elevated avalanche danger.

Summary

Weather Forecast

The storm continues through today bringing another 10cm+ to alpine elevations along with moderate SW winds.  Freezing levels are expected to rise to 1800m today making for moist snow conditions at lower elevations. 

Snowpack Summary

Another 7cm of snow at 1900m overnight. 70cm of storm snow overlies the Feb 27 interface which is a crust on solar aspects, and surface hoar/stellars on northerly aspects. Lee slopes feature large cornices with reactive windslabs downslope. Feb 10th surface hoar/crust is down 100cm+ and has been unreactive to tests. Moist snow below 1900m.

Avalanche Summary

A widespread avalanche cycle occurred yesterday mostly in the size 2-2.5 range. These slides were moist and were running to mid run out in most cases. The avalanche cycle is expected to continue today with freezing levels rising to 1800m, 12cm of snow forecast for higher elevations and moderate SW winds.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Wind Slabs

An icon showing Wind Slabs
Strong southerly winds have formed reactive slabs on lee features. Expect to find these slabs on northerly aspects near ridgline and crossloaded features.
If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
The Feb 27 crust/surface hoar layer down 70cm produces sudden results in stability tests.  If triggered this layer could propagate into a large avalanche.  Continued warm temperatures could see this layer failing as a moist slab at lower elevations.
If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Cornices

An icon showing Cornices
Large cornices have been formed by strong winds and storm snow.  Warm temperatures and continued loading may be enough to cause cornice failure.  Cornice fall has the potential to trigger persistent slabs on slopes below with large consequences.
Extra caution needed around cornices with current conditions.Pay attention to overhead hazards like cornices.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 7th, 2016 8:00AM