Avalanche Forecast

Issued: Mar 4th, 2015 7:56AM

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

rbuhler, Avalanche Canada

South Rockies.

Wind slabs may be lingering in the alpine. Use extra caution in wind loaded terrain.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

The ridge of high pressure continues to produce clear and dry conditions. Thursday should see a mix of sun and cloud. Freezing levels are expected to reach around 1500m as a warming trend begins heading into the weekend. Alpine winds on Thursday are expected to be moderate-to-strong from the NW. On Friday, similar conditions are expected with a mix of sun and cloud and moderate-to-strong NW winds in the alpine. However, freezing levels may reach over 2000m. On Saturday, freezing levels are forecast to remain around 2000m and increased cloud cover is expected.

Avalanche Summary

No new avalanches have been reported recently. Natural avalanches are generally not expected on Thursday but small human-triggered avalanches remain possible in isolated areas, specifically wind-loaded areas of the alpine.

Snowpack Summary

Up to 10 cm of new snow sits on the previous snow surface which was a mix of surface hoar, crusts, wind affected surfaces, and/or dry powder. Periods of moderate northerly winds have produced pockets of wind slab in exposed lee terrain. The most prominent snowpack features is a thick supportive crust around 10-30 cm below the surface. It extends up to around 2200m. Below this elevation the crust is effectively capping the snowpack, preventing riders from stressing deeper persistent weak layers. In alpine areas where the crust is not present or is less thick, it could still be possible to trigger a deep avalanche from rocky sun-exposed slopes, thin snowpack areas, or with a heavy load (i.e. cornice fall).

Problems

Wind Slabs

New snow amounts vary from only a few centimetres to around 10 cm. This snow arrived with moderate N-NE winds, which has switched to W-NW winds. Watch for pockets of wind slab on a variety of slopes in exposed terrain.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

Deeper weaknesses still exist and remain a concern in shallow rocky areas or anywhere the thick near-surface crust is weakening or non-existent, specially north aspects above 2200m.

Be aware of thin areas and rock outcroppings where it may be possible to initiate an avalanche that fails on one of the deeply buried weak layers.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

3 - 6

Valid until: Mar 5th, 2015 2:00PM