Avalanche Forecast

Archived

Jan 4th, 2023–Jan 5th, 2023

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 unlikely, human triggered possible.

Regions

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

As we approach the weekend, light inputs of new snow and increasing winds are going to promote slab development over a persistent and reactive weakness. Practice conservative travel techniques, stay diligent, and be skeptical when considering dropping into any steep or open slopes.

Confidence

Moderate

Avalanche Summary

No new avalanches observed or reported in the forecast region.

Snowpack Summary

Widespread SH growth in the 3 Valley Confluence around Jasper. The top 20-40cm is sitting on the active, persistent weakness (Dec 17 PWL), with varied slab density and some windslab development in open areas TL and above. Large facets, obvious in the lower snowpack make up the beginnings of the deep persistent weakness as part of the early season facet/depth hoar combo in the bottom of the snowpack. HS ranges from 50-120cm.

Weather Summary

A surface ridge continues to dominate the forecast through the end of the week. The ridge will weaken slightly on Thursday bringing increasing clouds and light precipitation leading into the weekend. Temperatures will be seasonal with a slight warming trend into the weekend.

Terrain and Travel Advice

The trees are not a safe haven, travel at treeline requires expert knowledge and diligence.
Make conservative terrain choices and avoid overhead hazard.

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.