Avalanche Forecast
Issued: Apr 15th, 2017 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Cornices and Persistent Slabs.
conrad janzen,
Avalanche Canada
Travel and ski conditions should improve for Sunday and Monday but watch for newly formed wind slabs and cornices, as well as the effects of daytime heating as the skies clear.
Summary
Weather Forecast
Moderate to strong west winds with light snowfall will continue through Saturday night before easing up on Sunday morning. Freezing levels will creep higher Sunday and higher still Monday with increasing solar influence as a ridge and clearing skies arrives on Sunday afternoon.
Snowpack Summary
5cm of new snow over a melt freeze crust on all aspects at tree line, and up to 2900m on solar aspects. 20-50cm of snow over the last week in the alpine. Moderate west winds creating soft slabs and rapid cornice growth. At tree line and above the mid-pack is a 120cm+ firm slab with few weaknesses. Thin snow pack areas may have weaker basal facets.
Avalanche Summary
Reports of a couple skier triggered wind slabs in the alpine at Bow Summit and Cathedral Peak on Friday as the winds increased. Propagation up to 100m was reported. On Saturday local ski areas were seeing rapid cornice growth and were able to ski cut small wind slabs in lee areas throughout the day. No new naturals observed but visibility was poor.
Confidence
Problems
Wind Slabs
Moderate to strong west winds with new snow have created soft slabs in the alpine. Skier triggering will remain likely through Sunday. Use caution if entering steep lee loaded areas and expect sluffing in steep gullies until the winds ease off.
- Minimize overhead exposure during periods of heavy loading from new snow, wind.
- The new snow will require several days to settle and stabilize.
Aspects: North, North East, East, South East, South.
Elevations: Alpine.
Likelihood
Expected Size
Cornices
Moderate to strong west winds have been rapidly building cornices over the past two days. Minimize your time underneath these and remember that a cornice failure could also trigger the persistent slab in thin snowpack areas.
- Give cornices a wide berth when travelling on or below ridges.
- Pay attention to overhead hazards like cornices which could trigger slabs.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
The snowpack is gaining strength, however the facets deeper in the snowpack remain a concern in thin alpine areas and where a cornice could trigger the slope. These facets do exist in isolated treeline areas, but are not currently a problem.
- Choose the deepest and strongest snowpack areas on your run.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 16th, 2017 4:00PM
