Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Apr 18th, 2014–Apr 19th, 2014

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural and human triggered avalanches likely.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural and human triggered avalanches likely.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.

Regions

Northwest Coastal.

This bulletin was created using very limited field data. If you are out in the mountains, please send your observations to [email protected]

Confidence

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

Weather Forecast

Unsettled conditions and light precipitation are expected for most of Saturday before the next low pressure system hits the north coast Saturday evening. Precipitation will ease a bit during the day on Sunday before a second pulse arrives Sunday evening. Light precipitation is expected for Monday. Saturday: Precipitation 2-5mm, freezing level am: 900m pm: 1300m, ridgetop wind: moderate-strong SE-SWSat. Night: Precipitation 8-15mm, ridgetop wind: strong SE-SWSunday: Precipitation 4-6mm, freezing level am: 1000m pm: 1200m, ridgetop wind: strong SE-SWSun. Night/Monday: Precipitation 6-12mm, freezing level am: 800m pm: 1100m, ridgetop wind: moderate-strong S-SW decreasing to light SE-S

Avalanche Summary

No new reported but this is likely due to a lack of observers.  Some natural avalanche activity is expected at higher elevations.

Snowpack Summary

10-40cm of new snow may sit on a crust which exists up to around 1400m on solar aspects or on last week's storm snow (90cm+ in areas of the region). Winds slabs have formed in lee features at treeline and above from strong S-SW winds.Recent warmer temperatures have helped to settle the underlying snowpack. In shallower snowpack areas or on steep, unsupported features, the old storm slab may still be reactive to human-triggering. This older storm slab is sitting on a surface hoar, a crust, and/or facets buried at the beginning of April. Large cornices may still be a concern, especially during periods of warming or heavy loading. The early February crust/facet layer is typically down 1.5 to 2.5m. A smaller avalanche or a cornice fall may still have the potential to step down to layer causing very large, destructive avalanches.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

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.