Sea to Sky Avalanche Forecast

Issued: Apr 12th, 2021 4:00PM

Tue Apr 13th Current Conditions
Alpine Moderate Treeline Moderate Below Treeline Moderate
Wed Apr 14th 2 Day Outlook
Alpine Considerable Treeline Considerable Below Treeline Considerable
Thu Apr 15th 3 Day Outlook
Alpine Considerable Treeline Considerable Below Treeline Considerable

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

Sunny weather and warm temperatures will increase the likelihood of wet loose avalanches on sun-exposed slopes, and cornice failure. Expect to find pockets of wind slab at upper elevations, which may be reactive to human triggers.

Summary

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

A ridge of high pressure, with sunny skies and high freezing levels will dominate the weather pattern this week.

Monday night - Mainly clear / strong northeast wind / alpine low temperature near -7 / freezing level 800 m 

Tuesday - Mainly sunny / light to moderate northeast wind / alpine high temperature near -3 / freezing level 2000 m 

Wednesday - Sunny / moderate northeast wind / alpine high temperature near 2 / freezing level 2700 m 

Thursday - Sunny / light northeast wind / alpine high temperature near 2 / freezing level 2600 m

Avalanche Summary

There have been several size 1-2 natural and human triggered storm and wind slab avalanches reported over the past few days. These were mainly on northerly aspects in the alpine and at treeline. There have also been several reports of cornice failures, and small wet-loose avalanches.

Looking forward, wind slabs are still possible to trigger at upper elevations, and wet-loose avalanches are expected with sun and warm temperatures. The likelihood of cornice failure also increases with warming.

Snowpack Summary

A storm late last week brought anywhere from 10-30 cm of new snow. The snow surface is now likely a crust in most areas, except on north aspects above about 1400 m where both soft snow and wind slabs may exist. In areas where the surface is a crust, sunshine and rising freezing levels are expected to soften the crust during the day.

Cornices are large and looming along ridgelines. Their release is unpredictable, requiring a large berth if you're travelling above or below them. Forecast rising freezing levels will increase the chances of cornice releases.

Terrain and Travel

  • Loose avalanches may start small but they can grow and push you into dangerous terrain.
  • Avoid sun exposed slopes, especially if snow surface is moist or wet.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.

Problems

Loose Wet

An icon showing Loose Wet

Likelihood

Possible-Likely

Expected Size

1 - 2

Surface snow will lose cohesion and become unstable with sunshine and rising freezing levels during the day. Avoid exposing yourself to terrain where a small wet loose avalanche could have big consequences.

Aspects:

South East, South, South West, West.

Elevations:

All elevations.

Cornices

An icon showing Cornices

Likelihood

Possible

Expected Size

2 - 3

Cornices are large and looming along many ridgelines, and have grown with recent fresh snow and wind. They become increasingly unstable during periods of warming.

Aspects:

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

Elevations:

Alpine.

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Isolated wind slabs may still react to human triggering in steep features at ridgecrest.

Aspects:

All aspects.

Elevations:

Alpine.

Valid until: Apr 13th, 2021 4:00PM

Forecast Trend

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