Avalanche Forecast

Issued: Feb 19th, 2023 4:00PM

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

Avalanche Canada jpercival, Avalanche Canada

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6:45 AM Update: Avalanche danger will rise over the day as new slabs form. Travel in avalanche terrain is not recommended if you find 30+ cm of new snow.

Summary

Confidence

Moderate

Avalanche Summary

On Saturday A few small (size 1) windslabs were reported that were initiated with ski cut testing on small steep slopes, depths estimated at 40 cm.

On Thursday, A large (size 2.5) avalanche was observed during a helicopter observation flight. This naturally trigger slab avalanche was approximately 80 to 100 cm deep. It initiated at the ridgetop, 2000 m elevation, running 250m in length. This very steep and rocky terrain feature was on a northeast aspect and it is suspected that the avalanche ran on a crust formed mid-January. Noted large (size 2) glide slab activity was confined to steep south aspect rock faces between 1600 and 1800 m elevation.

Please continue to post your reports and photos to the Mountain Information Network.

Snowpack Summary

Southwest winds continue redistributing 20 to 35 cm of available snow into lee features at higher elevations. On steep solar surfaces, you will find a thin melt-freeze crust. In sheltered areas, 20 to 30 cm of recent storm snow remains unconsolidated, this overlies an additional 50 cm of past HST that has settled and is well bonded.

A melt-freeze crust formed in mid-January is now buried up to 80-120 cm deep. At the moment this layer appears to be gaining strength but remains a concern. In isolated areas, small facets are still found above the crust. The snow below this layer is consolidating nicely. Buried 120-150 cm is a crust, formed near the end of December.

Snowpack depths are just below seasonal averages. Total amounts range from 150 to 300 cm at treeline, but decrease significantly below 1500 m.

Weather Summary

Sunday Night

Cloudy with continued moderate to heavy snowfall, 10 to 35 cm of accumulation. Winds southwest 50 km/h gusting to 70 km/h. Treeline temperatures -2 °C and freezing levels of 1000 m. 

Monday

Cloudy with moderate to heavy snowfall beginning in the late afternoon, 10 to 30 cm accumulation. Winds west 60 km/h gusting 80 km/h. Treeline temperature -2 °C. Freezing level 1000 m.

Tuesday

Cloudy with continued light to moderate snowfall, 5 to 10 cm of accumulation. Winds west 40 km/h easing to 10 km/h. Treeline temperatures -6 °C and freezing levels of 600 m. 

Wednesday

Clearing with no forecast precipitation. Winds east 20 km/h. Treeline temperatures -9 °C and freezing levels 0 m. 

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
  • Avoid areas with a thin or variable snowpack.

Problems

Wind Slabs

An icon showing Wind Slabs

Southwesterly winds are continuing to redistribute 20 cm of available snow into fresh wind slabs on north and east slopes at all elevations. Wind slabs may be sitting on a crust making them especially reactive and sensitive to skier triggering.

Expected northerly winds will begin building new and reactive wind slabs in exposed alpine and upper treeline features. Continue to use caution on lee features and watch for areas that have been reverse-loaded and cross-loaded.

Reports have outlined continued cornice growth and some failure of cornice tabs on the north aspect terrain. These growing problems can present as a trigger for windslabs that have formed below.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

A melt-freeze crust formed in mid-January is widespread throughout this forecast region and can be found down 70 to 90 cm. The terrain features that present the highest likelihood of triggering are where the snowpack is thin and steep rocky terrain features exist.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Feb 20th, 2023 4:00PM