Sea to Sky Avalanche Forecast

Issued: Mar 31st, 2021 4:00PM

Thu Apr 1st Current Conditions
Alpine Moderate Treeline Low Below Treeline Low
Fri Apr 2nd 2 Day Outlook
Alpine Moderate Treeline Low Below Treeline Low
Sat Apr 3rd 3 Day Outlook
Alpine Considerable Treeline Moderate Below Treeline Moderate

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

Changing wind has sifted the recent storm snow onto a variety of aspects at upper elevations. Wind slabs may be reactive to skier and rider triggering. Signs of wind slab instability include stiff snow and shooting cracks while you travel, whumphing and hollow sounds. 

Summary

Confidence

High -

Weather Forecast

A frontal wave will bring unsettled conditions including cloudy skies and light snow amounts.

Wednesday Night: Cloudy with alpine temperatures near -3. Ridgetop wind strong from the southwest and freezing levels 800 m. 

Thursday: Cloudy with flurries. Ridgetop wind light from the southwest. Alpine temperatures near -4 and freezing levels 1200 m. 

Friday: Cloudy with flurries. Ridgetop wind light from the southwest. Alpine temperatures -7 and freezing levels 1000 m.

Saturday: Snow amounts 10-20 cm with moderate ridgetop wind from the southwest. Freezing level 1200 m.

Avalanche Summary

No new avalanche reports by Wednesday afternoon.  

On Tuesday, reports indicated that small loose wet avalanches occurred from steep rocky terrain. Cornices also became weak and failed with daytime warming. No slabs were reported from the slopes below. 

Wind slabs may be reactive to human triggering on wind-loaded slopes at upper elevations. Cornices are fragile and pose a threat from above and below. 

Snowpack Summary

Up to 40 cm of snow fell throughout the region since the weekend. This was accompanied by strong southwest winds that switched to the northwest. Reactive wind slabs could be lingering on a variety of aspects at upper elevations, especially where they sit above a crust. 

The recent snow sits above a variety of old snow surfaces comprising mostly of a widespread melt-freeze crust with the exception of high north-facing terrain where it may be sitting on small surface hoar crystals. A melt-freeze crust exists at treeline and an isothermal trend exists below 1100 m.

Cornices along ridgelines are large, and the likelihood of them failing will increase when the sun comes out.

Terrain and Travel

  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Be aware of highly variable recent wind loading patterns.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Seek out sheltered terrain where new snow hasn't been wind-affected.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Changing wind from southwest to northwest has added complexity to the snow loading pattern. You may find reactive wind slabs on unsuspecting slopes and on a variety of aspects, especially where the slab sits above a crust or feathery surface hoar crystals that were possibly buried on high northerly, wind-sheltered slopes. .

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Cornices

An icon showing Cornices

Likelihood

Possible

Expected Size

2 - 3

Cornices are large and looming along many ridgelines, and have likely grown with the recent snow and wind. They require respect and a large berth if you're travelling above or below. 

Aspects:

North, North East, East, West, North West.

Elevations:

Alpine.

Valid until: Apr 1st, 2021 4:00PM

Forecast Trend

The latest forecast danger ratings, broken down to elevation. See how an elevation is trending.