Avalanche Forecast

Archived

Mar 9th, 2024–Mar 10th, 2024

Alpine

Natural and human triggered avalanches likely.

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.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Pine Pass.

Avoid Avalanche Terrain

Ongoing snowfall and strong wind are forming reactive storm slabs over a weak snow pack.

Confidence

Moderate

Avalanche Summary

A few natural wind or storm slab avalanches have been reported on Friday morning in the Pine Pass area with the arrival of new snow and strong winds.

As new snow starts to accumulate and the load slowly starts to increase above buried weak layers, we expect persistent slabs to become more reactive.

Snowpack Summary

New snow is being redistributed by strong southwest winds, leaving widespread wind-affected surfaces in exposed terrain. The snow surface will likely become moist at low elevations.

30 to 60 cm below the surface a variety of potential weak layers may exist, including surface hoar in wind-sheltered terrain, weak facets, or a hard melt-freeze crust on south and west-facing slopes.

A thick and hard widespread crust that formed in early February is buried about 60 to 90 cm deep. This crust may have a layer of facets above it.

Weather Summary

Saturday Night

Mostly cloudy with up to 10 cm of new snow. 25 to 45 km/h southwest alpine wind. Treeline temperature -4°C.

Sunday

Mostly cloudy with 5 to 10 cm of new snow. 25 to 45 km/h southwest alpine wind. Freezing level rising to 1300 m.

Monday

A mix of sun and cloud with up to 5 cm of new snow. 15 to 35 km/h southwest alpine wind. Treeline temperature -1°C.

Tuesday

Mostly cloudy with around 5 cm of new snow. 20 to 40 km/h south alpine wind. Treeline temperature -1°C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Minimize exposure during periods of heavy loading from new snow and wind.
Conservative terrain selection is critical, choose only well supported, low consequence lines.
Remote triggering is a concern, watch out for adjacent and overhead slopes.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.

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.

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.