Avalanche Forecast

Issued: Mar 6th, 2020 1:00AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Persistent Slabs, Storm Slabs and Loose Dry.

Jesse Percival, VIAC

Vancouver Island.

This weekend is beginning with some spice. Thursday's active avalanche control program at Mount Washington, reported numerous size 1 to 1.5 storm slab avalanches triggered by ski cuts. Explosive control on a cornice feature triggered a size 2 avalanche, all on north thru to west aspects. A skier accidental avalanche was trigger on a North east aspect at the apex of a convex roll, no injuries have been reported or other details.

Summary

Past Weather

A strong cold front passed rapidly over the forecast area delivering intense snowfall and strong wind.

Weather Forecast

Unstable weather in the wake of the recent storm will bring to the forecast area a mixed bag of clouds moderate snowfall and a few periods of sun. Friday: 10-15 cm of snow, Winds Light from the South East, Freezing levels to 1000 meters.Saturday: 5 to 10 cm of snow, Winds Moderate from the South West, Freezing levels to 1000 meters.Sunday: 5 to 10 cm of snow, Winds Light from the South East, Freezing levels 1000 meters.

Terrain Advice

Careful and cautious route finding when transitioning into wind effected convex rolls or steep terrain.Default to lower angled terrain if you observe wind drifted snow, active snow transport, or snowfall amounts that exceed 30 centimeters.If precipitation amounts exceed forecast, expect hazard rating to be higher.

Snowpack Summary

New snow has fallen on a variety of old surfaces including solar crusts and old surfaces that are hard and planar.

Snowpack Details

Surface: New snow of up to ten centimeters overlies over a thin sun crust on solars and on old hard snow on non solars.
Upper: 30 to 100 cm of settled storm snow with a few thin crusts sandwiched between on solar aspects.
Mid: An old crust with weakening snow crystals above and below the crust as it continues to degrade.
Lower: Well settled and dense.

Confidence

Moderate - High value field data and feedback, but the weather models have a high degree of variability.

Problems

Persistent Slabs

Down between 35 to 100 cm this decomposing crust is the remnants of surface hoar and is becoming less reactive and is approaching dormancy. **Location:** On North aspects and found in both the Alpine and at Treeline. **Possibility:** Triggering of this avalanche problem is unlikely to possible from light loads such as skiers. Natural avalanches are unlikely. **Size:** If triggered expect these avalanches to be large on isolated terrain, size 3.

Likelihood

Possible

Expected Size

1 - 1

Storm Slabs

Found on predominantly North thru to East aspects, this new avalanche problem will begin to form as new low density snow begins to settle over a variety of crusts. **Location:** All aspects found in both the Alpine and at Tree line. **Possibility:** Triggering of this avalanche problem is likely to very likely from light loads such as skiers. Natural avalanches are possible to likely. **Size:** If triggered expect these avalanches to be large size 2, and on isolated terrain features very large, size 3.

Likelihood

Possible

Expected Size

1 - 1

Loose Dry

This new avalanche problem will be predominately small but in terrain with traps even a small avalanche can be hazardous. **Location:** All aspects found and all elevations. **Possibility:** Triggering of this avalanche problem is likely to very likely from light loads such as skiers. Natural avalanches are possible to likely. **Size:** If triggered expect these avalanches to be small size 1, and on isolated terrain features large, size 2.

Likelihood

Possible

Expected Size

1 - 1

Valid until: Mar 7th, 2020 1:00AM