Sea To Sky

Date Issued: Sun, 16 Dec 2018 00:19

Valid Until: Sun, 16 Dec 2018 22:00

Forecaster: istorm

Another several days of stormy weather will elevate the avalanche hazard. Stick to simple terrain. If you're at lower elevation but around avalanche paths think about what's above you and the possibility of a full-path avalanche.

Sun, 16 DecMon, 17 DecTue, 18 Dec
Alpine4 High4 High4 High
Treeline4 High4 High4 High
Below Treeline3 Considerable3 Considerable3 Considerable
Confidence: High - Intensity of incoming weather systems is uncertain
Sun, 16 DecMon, 17 DecTue, 18 Dec
Alpine4 High4 High4 High
Treeline4 High4 High4 High
Below Treeline3 Considerable3 Considerable3 Considerable
Confidence: High - Intensity of incoming weather systems is uncertain

Storm Slabs

Travel and Terrain Advice

  • The new snow will require several days to settle and stabilize.
  • Stick to simple terrain and be aware of what is above you at all times.
  • Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.

Forecast Details

Avalanche Summary

Last week's widespread natural avalanche cycle is slowing down. On Friday most reported avalanches were size 2 to 2.5 with crowns reported from 60 to 150 cm thick on all but windward aspects.

Human-triggered avalanches were my concern during Saturday's short-lived lull before the next storm ramps up overnight Saturday and really gets going Sunday.

Snowpack Summary

Up to 2 m of snow fell in the series of storms that started a week ago. Extreme southerly winds (up to 180 km/h!) accompanied the storms. Another series of storms is on the doorstep.

A crust likely exists on or near the surface at elevations below approximately 1700 m.

A weak layer of facets and surface hoar lies below the recent storm snow. Initially, avalanches were reported to be running on this layer. However, recent avalanche activity is running in the storm snow above this layer. Still, the presence of this layer shouldn't be completely discarded, since it could potentially increase expected avalanche size with a large trigger like a cornice collapse.

Weather Forecast

SATURDAY NIGHT: 10 to 20 cm new snow. Freezing level around 800 m. Moderate southerly winds.

SUNDAY: 15 to 35 cm new snow depending if you're in a snow-hole or not. Freezing level around 1200 m. Strong southerly winds.

MONDAY: Another 10 to 20 cm new snow. Freezing level dropping back to around 1000 m. Moderate southwesterly winds.

TUESDAY: Storm continues, new snow accumulations continue with another 20 or 30 cm forecast. Freezing level steady around 1000 m. Moderate southwest winds.