Avalanche Forecast

Archived

Jan 25th, 2024–Jan 26th, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

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 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.

Regions

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

Deep persistent slab avalanches have been reported in the region. Although triggered by explosives, this is a warning sign that this layer is reaching its threshold. As we enter a period of warming temperatures, be extra vigilant in your terrain choices.Keep in mind your overhead hazard during the warmest part of the day.

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

Friday

Cloudy with sunny periods. Precipitation: Nil. Alpine temperature: High -5 °C. Mostly light ridge wind occasionally gusting to 35 km/h. Freezing level: 1500 metres.

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

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.

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.

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.