Avalanche Forecast

Archived

Mar 5th, 2014–Mar 6th, 2014

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Glacier.

The steady snowfall, warming, and winds have gradually bumped the danger up. Keep your head up and avoid overhead hazards.

Weather Forecast

The main brunt of the storm will likely track south of Rogers Pass, but we'll still see some action. Forecasted snowfall is 10-15cm today, 5-10cm tonight, with freezing levels rising to 1300m and winds remaining moderate to strong from the SW.

Snowpack Summary

25-35cm of heavy snow over light snow has created a touchy soft slab. This has buried a suncrust on S and W aspects, and likely surface hoar in sheltered below tree-line areas. In the alpine and tree-line, strong N and E winds from the weekend created wind slabs which were also buried. The Jan 28/Feb 10 PWL is down 1-1.4m under a cohesive slab.

Avalanche Summary

A natural cycle occurred yesterday and overnight as the temperatures and winds picked up. Avalanches up to size 3 were running from steep gully features on all aspects in the alpine, especially east of Rogers Pass in the highway corridor. Several of the slides ran to the end of their path, deep down in the valley.

Confidence

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

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 Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.