Avalanche Forecast South Coast

Date Issued: Valid Until:

Avalanche Canada shorton, Avalanche Canada

Avalanche Forecast

Mon Mar. 11th ยท 3:19PM

Alpine

Danger Ratings High

Treeline

Danger Ratings High

Below Treeline

Danger Ratings Considerable
Storm Slabs Storm Slabs
Persistent Slabs Persistent Slabs

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Considerable

Below Treeline

Danger Ratings Moderate

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Considerable

Below Treeline

Danger Ratings Moderate
Avoid avalanche terrain on Tuesday. The new snow will need time to settle and gain strength.

Confidence

High -

Weather Forecast

MONDAY NIGHT: Heavy snowfall with accumulations of 20-30 cm, 30-60 km/h southwest wind, treeline temperatures around -2 C, freezing level around 500 m.TUESDAY: Snow continues in the morning with another 5-10 cm then eases off in the afternoon, total accumulation of 30-45 cm over the course of the storm, 20-30 km/h northwest wind as the storm eases, treeline temperatures near -2 C, freezing level 800 m.WEDNESDAY: Mix of sun and cloud, light northwest wind, treeline temperatures near -2 C, freezing level 800 m.THURSDAY: Cloudy with isolated flurries, 30-50 km/h southwest wind, treeline temperatures near +1 C, freezing level 1200 m.

Avalanche Summary

Avalanche activity over the weekend was limited to small slab and loose avalanches in the top 20 cm of snow (size 1). Looking ahead, the most likely problem will be fresh storm slabs, however the lingering persistent weak layer in the North Shore Mountains still poses a low likelihood - high consequence problem.

Snowpack Summary

30-45 cm of new snow will be accompanied with strong southwest wind. The new snow is falling on a sun crust on steep southerly slopes, and possibly on weak surface hoar crystals on sheltered and shaded slopes. The combination will form very touchy storm slabs on Tuesday.A layer of weak and sugary faceted grains sits on a melt-freeze crust about 50 to 120 cm deep. The layer is likely most prominent in the North Shore Mountains and on north aspects. This layer continues to be reactive in snowpack tests. The problem is not typical for the region and we expect this persistent weak layer to continue to linger.The lower snowpack is generally strong.

Problems

Storm Slabs

Storm Slabs

A natural avalanche cycle is expected to start on Monday night and human triggered storm slabs will remain very likely on Tuesday.

Avoid avalanche terrain during periods of heavy loading from new snow and wind.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2
Persistent Slabs

Persistent Slabs

A weak layer is buried 50 to 120 cm deep in the North Shore Mountains. The layer consists of weak faceted grains above a crust. This layer could become reactive with the additional load of the new snow.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Treeline.

Likelihood

Possible - Unlikely

Expected Size

2 - 3