Avalanche Forecast

Archived

Apr 14th, 2014–Apr 15th, 2014

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Northwest Inland.

This bulletin has been produced using very limited field data. If you've been out in the mountains we'd love to hear about what you've seen. Observations can be sent to [email protected]

Confidence

Fair - Due to the number of field observations

Weather Forecast

Tuesday: Light snowfall / Light to moderate southwest winds / Freezing level at 1000mWednesday: Mix of sun and cloud / Light to moderate southwest winds / Freezing level at 1250mThursday: Moderate snowfall / Moderate to strong southwest winds / Freezing level at 1250m

Avalanche Summary

At the time of publishing no new avalanches were reported, although I suspect natural loose wet and slab activity may have occurred with warm temperatures over the weekend.

Snowpack Summary

North facing alpine and upper treeline terrain is still likely seeing wintery conditions. Weather data suggests melt-freeze conditions exist in most other areas. Recent strong SW winds have built thick hard wind slabs on leeward aspects which overlie a crust, and recent test results indicate touchy conditions still exist. Cornices are also large and potentially weak.The early February crust/facet layer is down 150 - 200 cm. This destructive layer should become less likely to trigger with forecast cooling.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.