Avalanche Forecast

Archived

Mar 15th, 2023–Mar 16th, 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 unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Little Yoho.

Continued natural avalanches are expected on solar aspects over the next 24-48 hours, and cornice failures may continue to trigger the deep persistent layer on the lee aspects. Continue to avoid large avalanche terrain features and avoid climbing in gullies with any exposure to the sun.

Confidence

Moderate

Avalanche Summary

No new avalanches have been reported in this region.

To the east in the weaker snowpack, a deep size 3 on Pilot Mountain, a large, deep size 3 on Puzzle Peak crossed the standard uptrack (solar triggered probably). Finally, a large natural avalanche in Kananaskis Country ran over some ice climbs on Mt. Kidd.

Snowpack Summary

3-day storm totals Sunshine 21 cm, Simpson, 13 cm, Stanley 12 cm, Bosworth 25 cm and Bow Summit 34 cm.

This new snow has fallen on a freshly buried (March 12) layer of surface hoar, facets and sun crust and in the next few days we will see how well it bonds. Generally, we expect the snowpack to settle well over the next few days as the storm snow finds its place. The basal facets are less pronounced in this region with deeper snowpack and will become less reactive over the next few days.

Weather Summary

Sunny skies are forecasted for Thursday with afternoon cloudy periods. Light morning N-NW winds will ease to very light westerly. Freezing levels between 1300 to 1500 m with alpine temperatures ranging between -10 to -15C. Friday & Saturday, clear skies continue, daytime freezing levels climb to 1800 m with warmer alpine temperatures ranging between -5 and -10 C.

For a more detailed forecast click here.

Terrain and Travel Advice

Uncertainty is best managed through conservative terrain choices at this time.
Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

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.

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.