Avalanche Forecast

Issued: Mar 19th, 2019 4:22PM

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

swerner, Avalanche Canada

Sea To Sky.

Persistent warm temperatures are penetrating and destabilizing the upper snowpack. Natural avalanche activity is possible especially on sun exposed slopes. Avoid travel under avalanche paths especially with looming cornices overhead.

Summary

Confidence

Moderate -

Weather Forecast

WEDNESDAY: A mix of sun and cloud with alpine temperatures near +9 degrees. Ridgetop winds moderate from the East and freezing levels above 3000 m. Alpine temperature inversion.THURSDAY: Cloudy. Alpine temperatures +6 degrees with freezing levels 2000 m. Ridgetop winds light from the southwest. FRIDAY: Cloudy with isolated rain showers and some flurries at higher elevations. Alpine temperatures near +1 degrees and freezing levels dropping to 1800 m. Ridgetop winds moderate from the South.

Avalanche Summary

Reports indicated evidence of a natural loose wet avalanche cycle up to size 2 on Monday evening. Skier triggered loose wet avalanches were easily triggered up to size 1.5 and lots of snowballing and sluffing.With continued warming we expect to see natural avalanche activity to continue on all aspects and elevations.

Snowpack Summary

Snow surfaces are highly variable. On higher elevation northerly aspects (above 1900 m) you may find some dry, faceted snow. Some of this has been redistributed by southwesterly and northerly winds, potentially creating some unusual wind slabs. On solar aspects (East, South, West) moist snow exists creating melt-freeze conditions at higher elevations and mostly just melt conditions below treeline. The bigger questions are deeper in the snowpack. With little overnight re-freeze the warm temperatures will penetrate deeper and continue to destabilize the snowpack. Its hard to say how many hot days and warm nights it will it take to wake up the more deeply buried weak layers that we haven't thought about in a long time. Currently, the snowpack is complex and with the continued warming and little overnight re-freeze natural avalanche activity remains possible.

Problems

Loose Wet

Loose wet activity is expected to continue on all aspects and elevations except northerly alpine slopes. Cornices are soft and weak. You don't want to be under or near one of these monsters when they fail.

Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.Cornices become weak with daytime heating or solar exposure.Loose avalanches may start small but they can grow and push you into dangerous terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Wind Slabs

Continued warm temperatures will further destabilize the upper 30 to 50 cm of snow which has potential to fail naturally.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Back off slopes as the surface becomes moist or wet with rising temperatures.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: North, North East, North West.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1.5 - 2

Valid until: Mar 20th, 2019 2:00PM