Avalanche Forecast

Archived

Mar 9th, 2022–Mar 10th, 2022

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Little Yoho.

Go for shady aspects right now, the snow is cold and dry here. The sunny side of the mountain holds buried crusts that are proving unpredictable in their location, the overlying slab and the likelihood of triggering. Uncertainty demands wide margins.

Weather Forecast

The next few days will warm slowly as the weather pattern changes. The NW flow continues, but a low pressure system will cross the area starting Thursday bringing trace amounts of snow, light to moderate winds and temperatures a few degrees warmer each day. No significant inputs to change the avalanche hazard are expected for the next few days.

Snowpack Summary

5-10 cm of low density snow sits over a sun crust on steep solar aspects that exists up to about 2600 m. North winds overnight Wed may develop wind effect and small windslabs in the alpine. February 16 sun crust down 30-40 cm on west, south and east aspects. January 30 facet or sun crust interface is down 50-80 cm. Lower snowpack is well settled.

Avalanche Summary

On Tues a skier triggered a large persistent slab (size 3.5) on the southeast slope of Vermillion Peak. No involvement was reported but this is a wake-up to the potential on this crust. Also on Tues we received a report of a cornice triggered size 2.5 slab avalanche on Mt. Carnarvon in Yoho - this one also likely ran on the crust. Note the pattern.

Confidence

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.