Avalanche Forecast

Archived

Jan 26th, 2024–Jan 27th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Maligne, Marmot, Miette Lake, Pyramid.

The avalanche hazard is expected to rise over the weekend with the incoming warm temperatures.

Watch for signs of instability, especially snowballing and loose wet avalanches, that indicate the rising temperatures are effecting the snowpack, and the possibility of Deep Persistent Avalanches is increasing.

Confidence

Moderate

Avalanche Summary

Marmot Basin has reported a few explosive triggered large deep persistent slabs in the alpine on north aspect. Parkway patrol did not observe any new natural avalanche activity on Thursday. A few small loose wet slides have been observed along the Maligne Road on solar aspects, in steep rocky terrain below the tree line.

Snowpack Summary

The snowpack continues to be weak and largely unsupportive, though recent storm snow has improved travel. HS at tree-line is 45-75cm. Ski penetration is down ~30cm which shows that there is some structure (slab) in the mid-pack. An interface down ~25cm shows up in snowpack tests; while in the field, reactivity will be subject to the strength of the slab over the PWL layer. Expect temperature crusts at lower elevations as freezing levels rise above valley bottom.

Weather Summary

Unseasonably warm conditions will begin to move into the area on Saturday, with freezing levels rising to between 1600 and 1800m.

The Mountain Weather Forecast is available at Avalanche Canada https://avalanche.ca/weather/forecast

Terrain and Travel Advice

Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.

Problems

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.

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.