Avalanche Forecast

Issued: Mar 13th, 2021 4:00PM

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

Avalanche Canada mconlan, Avalanche Canada

Email

Storm and wind slabs should build over the day as a storm impacts the region. Treat the danger as HIGH if 25 cm of snow or more accumulates in your riding area.

Summary

Confidence

Moderate - Uncertainty is due to the track & intensity of the incoming weather system.

Weather Forecast

SATURDAY NIGHT: Increasing clouds, 40 to 60 km/h south wind, treeline temperature 1 C, freezing level 1500 m.

SUNDAY: Cloudy with snowfall, accumulation 20 to 30 cm, 40 to 60 km/h south wind, treeline temperature -2 C, freezing level 1000 m.

MONDAY: Mix of sun and cloud, 20 km/h northeast wind, treeline temperature -3 C, freezing level 1000 m.

TUESDAY: Mostly cloudy, 20 km/h northwest wind, treeline temperature 2 C, freezing level 900 m.

Avalanche Summary

Loose wet activity and some cornice failures have likely occurred in the past few days from spring-like conditions. Looking forward, storm and wind slabs are likely to be triggerable on Sunday as they build during and after the storm. Loose wet avalanche activity may continue below the rain-snow line.

Snowpack Summary

A storm will impact the region on Sunday, bringing snow above around 1000 m, and rain below. Storm slabs are expected to rapidly form over the day. Below the rain-snow line, rain will soak an already wet snowpack. Strong south wind will form wind slabs in exposed lee terrain features at treeline and alpine elevations. The snow will fall onto previously wet or crusty snow except at high elevation northerly aspects, where it should fall onto wind-affected snow in exposed terrain or perhaps small surface hoar crystals in sheltered terrain. Cornices have been reported as being massive and fragile.

Terrain and Travel

  • Wind slabs are most reactive during their formation.
  • Dial back your terrain choices if you are seeing more than 20 cm of new snow.
  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
  • Extra caution is needed around cornices under the current conditions.

Problems

Storm Slabs

An icon showing Storm Slabs

Storm and wind slabs will build over the day as a storm impacts the region. Storm slabs will rapidly build above the rain-snow line, rain will soak the snow below, and wind slabs are expected to form in lee terrain features at treeline and alpine elevations. It will be safest to avoid avalanche terrain during periods of rapid snowfall (2-3 cm per hour) and if you find 25 cm or more new snow.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Mar 14th, 2021 4:00PM