Avalanche Forecast

Issued: Mar 30th, 2014 9:37AM

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.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Monday

Weather Forecast

Synopsis: The trough that delivered snow through the weekend is starting to weaken, giving way to sunny skies and seasonably cool temperatures.Monday: Freezing Level: 1300 - 1600m; Precipitation: Nil; Wind: Treeline: Light, E | Ridgetop: Light, SETuesday: Freezing Level: 1400 - 1700m; Precipitation: Nil; Wind: Treeline: Light, Variable | Ridgetop: Light, NWWednesday: Freezing Level: 1300m - 1500m; Precipitation: Trace; Wind: Treeline: Light, W | Ridgetop: Light, W

Avalanche Summary

On Saturday avalanches ran naturally and were triggered by riders to size 2. New snow resting on a thin melt freeze crust was quite reactive. Reports from Saturday included remote triggering at this interface. All avalanche activity from Saturday was limited to the surface. We did not receive reports of any activity or step down events to the older persistent weak layers.

Snowpack Summary

The weekend storm produced 15 - 70 cm of new snow. Below 2100m , on all aspects, this snow rests on thin melt freeze crust that was very reactive on Saturday. (The exception is north facing terrain above 1500m where the crust is not present.) The first part of the storm was accompanied by strong southerly winds that formed Isolated wind slabs immediately below ridge crest. This snow adds additional load to the mid March surface hoar / crust interface, now down 80 - 110cm. The bond at this interface is improving making it less susceptible to human 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

Cool temps and mostly cloudy skies should help this interface to settle out, but remain vigilant for potentially sensitive wind slabs immediately lee of ridge crest. Direct sun and warming temps could initiate natural activity.

Use ridges or ribs to avoid pockets of wind loaded snow.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>The new snow will likely require another day to settle and stabilize.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

Two deep weak layers exist in the snowpack. These weak layers could be activated by cornice fall, a surface avalanche in motion, or a rider finding the sweet spot, likely near a rock outcropping, or anywhere the snowpack goes from thick to thin.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 31st, 2014 2:00PM