Avalanche Forecast

Issued: Apr 2nd, 2014 9:17AM

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

ghelgeson, Avalanche Canada

Sea To Sky.

Avalanche hazard will likely increase throughout the day, be sure your plans allow for a safe retreat from the mountains.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Synopsis: The front breaks down Wednesday night opening the door to zonal flow. A series of weak disturbances should deliver daily precipitation through the weekend.Thursday: Freezing Level: 1000m - 1700m; Precipitation: 1:6mm - 1:10cm; Wind: Treeline: Light, S | Ridgetop: Strong, SWThursday Night: Precipitation: 1:8mm - 1:15cmFriday: Freezing Level: 1100m - 1700m; Precipitation: 1:5mm - 1:10cm; Wind: Treeline: Moderate, SW | Ridgetop: Strong, SWFriday Night: Precipitation: 1:5mm - 1:10cmSaturday: Freezing Level: 1300m - 1900m; Precipitation: 1:6mm - 1:10cm; Wind: Treeline: Light, SW | Ridgetop: Strong, SW

Avalanche Summary

Warming temps induced cornice fall Tuesday. A notable event occurred on a NE facing slope at 2100m when a falling chunk of cornice triggered a small slab immediately below the ridge. The avalanche in motion stepped down to what was likely the late March crust resulting in a size 2.5 avalanche. Another large natural avalanche was reported from a W/SW facing feature at 2300m. This one failed on the same interface, likely initiated by Tuesday's intense solar.

Snowpack Summary

The snow surface is a mix of surface hoar and melt freeze crusts.Recent warm temperatures have helped to settle and strengthen the upper snowpack. Down 15 - 70 cm below the surface, snowpack tests are still producing results on the late March crust.The mid March surface hoar/ crust interface now down 80 - 110cm seams to be decreasing in it's sensitivity to triggering.The early-March crust/facet layer is down about 100-150 cm and the early February layer is now down close to 200 cm. These layers are largely dormant at this time.The lower snowpack is strong and well settled.

Problems

Storm Slabs

New snow accompanied by strong wind should result in new slabs being formed on top of surface hoar and crusts by mid afternoon. I expect these touchy slabs will become more and more problematic as the day goes on.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

Three buried weak layers exist in the snowpack. These weak layers could be activated by cornice fall, a smaller surface avalanche in motion, or a rider finding the sweet spot, which would be most likely in steep rocky terrain.

Be aware of the potential for large, deep avalanches due to the presence of buried facets and surface hoar.>Extra caution needed around cornices with current conditions.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Valid until: Apr 3rd, 2014 2:00PM