Avalanche Forecast

Archived

Mar 15th, 2024–Mar 16th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Widespread avalanches certain.

Treeline

Widespread avalanches certain.

Below Treeline

Widespread avalanches certain.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Glacier.

Temperatures are forecast to remain above freezing overnight well in to the alpine.

As the day warms Saturday, widespread natural avalanches are expected, and have the potential to step down to the Feb 3rd crust/facet combo.

Travel in avalanche terrain is not recommended.

Confidence

Moderate

Avalanche Summary

Natural avalanche activity picked up Friday afternoon, with ongoing warming. We observed several large loose and wet slab avalanches from solar aspects. There was a notable size 3 persistent slab avalanche beside the Grizzly couloir.

Expect natural avalanches to increase in size and frequency with continued warming.

Natural avalanches on the persistent weak layer (over 1m deep) are expected to become widespread as the warmth penetrates deeper into the snowpack.

Snowpack Summary

Radiant cooling during the clear night may create a weak surface crust. Above freezing temps into the alpine will quickly weaken the surface snow on all aspects as the day warms.

A previous suncrust, down 20-40cm, may make a sliding layer for wet slabs.

80-140cm of settled snow sits above a sugary facet layer. These facets are poorly bonded to the widespread, firm crust from Feb 3rd. This is a significant persistent weak layer and will be a concern for the foreseeable future.

Weather Summary

Temperatures continue to rise, with a mass of warm air driving freezing levels up above 3000m (mountain top) over the next couple days.

Tonight: Alpine low 2°C, with a temperature inversion. Light W ridgetop winds.

Sat: Mainly cloudy. Alpine high 3°C, Freezing level (FZL) 2900m. Light W winds.

Sun: Sun/cloud. Low 3°C, High 7°C. FZL 3300m. light SW winds.

Mon: Sun/cloud. Low 2°C, High 4°C. FZL 2500m. Light SW winds.

Terrain and Travel Advice

Avoid exposure to overhead avalanche terrain as temperatures increase.
If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
Avoid traveling in runout zones. Avalanches have the potential to run to the valley floor.

Problems

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.

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.

Wet Slabs

Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.