Avalanche Forecast

Archived

Mar 27th, 2023–Mar 28th, 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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Little Yoho.

The increased hazard rating reflects the possibility of loose wet avalanches activity due to solar heating Tuesday. Minimize exposure to sun-exposed slopes when the solar radiation is strong.

Confidence

Moderate

Avalanche Summary

A skier trigger avalanche was reported on Mt Field Saturday. The recent storm has been causing loose dry avalanches in steep terrain. Solar inputs Tuesday will likely affect this storm snow, causing loose dry avalanches.

Snowpack Summary

5-20 cm of storm snow sits over buried temperature crusts to 1500 m, sun crusts to ridgetop on solar aspects, and facets on shaded slopes. The midpack in this area has several crust and facet layers that have been unreactive recently. The base of the snowpack still consists of weaker facets. These facets are mostly a concern in thinner snowpack areas (<2 m).

Weather Summary

A ridge of high pressure will bring clear skies to the region. Overnight alpine temps for Monday and Tuesday will be near -20 with daytime highs climbing to 0 at 2000m. Winds will remain Light to Moderate. Though temps will be cold overnight, strong solar inputs throughout the day will likely cause the upper snowpack to deteriorate.

Terrain and Travel Advice

Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Cornices become weak with daytime heating or solar exposure.
Minimize exposure to sun-exposed slopes when the solar radiation is strong.

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.

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.