Avalanche Forecast

Issued: Mar 26th, 2013 9:47AM

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

pgoddard, Avalanche Canada

Sea To Sky.

Avalanche danger may rise with solar radiation or daytime warming.

Summary

Weather Forecast

Wednesday: Very light snow. Light S winds. Alpine temperature near -1. Thursday: Light snow. Light S winds. Freezing level near 1800 m.Friday: Clearing. Light winds. Freezing level near 1800 m.

Avalanche Summary

Small loose snow avalanches were reported in response to solar warming on Monday. A skier was partially buried in a slab in the Callaghan Valley on Sunday (report here).There was a report of a skier triggered size 2 slab avalanche on Saturday from a rocky south-facing alpine slope, in an area just north of Whistler. A few natural cornice falls also triggered thin slabs up to size 2 on the slope below.

Snowpack Summary

Warm temperatures are helping recent storm snow to settle. On sun-baked and low to mid elevation slopes, a melt-freeze cycle is in play at the snow surface. This is causing weak moist snow conditions by day, while a refrozen crust forms by night. Large cornices are looming over some slopes, which may be weakened with warm temperatures.Various melt-freeze crusts are buried in the upper snowpack. In general, the bond at these interfaces is improving. A layer of surface hoar (buried on March 11; now down about 90 cm) is still being observed in some locations, with hard results in snowpack tests. Mid and lower snowpack layers are well bonded.

Problems

Cornices

Cornices are large and weak. Daytime warming and sunshine could cause cornices to fail, possibly triggering a slab on the slope below.

Give cornices a wide berth when travelling on or below ridges.>

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 6

Loose Wet

Direct sun may trigger loose snow avalanches on steep sunny slopes.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: North, North East, East, South East, South.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Mar 27th, 2013 2:00PM