Avalanche Forecast

Issued: Apr 21st, 2013 10:48AM

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

swerner, Avalanche Canada

Sea To Sky.

The Public Avalanche Forecasts will come to an end on Tuesday. General spring messaging will be found under the "Forecast Details" tab below.See you next season!

Summary

Confidence

Good

Weather Forecast

An upper ridge stalls off the coast bringing sunny skies and dry cooler conditions through Tuesday. By mid-week freezing levels will gradually start to rise near 2000 m.Monday: Mostly clear skies. Ridgetop winds light-moderate from the NW and freezing levels reaching 1800 m. Tuesday: Mix of sun and cloud. Possible light pulses of precipitation. Ridgetop winds light from the NE and freezing levels rising to 1900 m. Wednesday: The stationary ridge of high pressure continues bringing sunny skies freezing levels up to 2400 m. Ridgetop winds will blow light from the West.

Avalanche Summary

No new avalanche activity reported. Be aware that avalanche danger can increase quickly under the influence of the sun.

Snowpack Summary

Variable amounts of snow fell throughout Thursday night and Friday with the greatest accumulations falling in the south of the region. More recent rain and warm temperatures have left snow surfaces moist to about 1950m. Cohesive new wind slabs exist at higher elevations.In the upper snowpack (down 50-70cm) a significant melt-freeze crust lingers. Some facetting has been observed above and below this crust. At the same interface spotty surface hoar may linger on high, sheltered north facing terrain. My best guess is that this interface has gained significant strength, although I would make further observations before committing to any steep, unsupported features in the alpine.Cornices are huge and will continue to grow with the forecasted precipitation.

Problems

Loose Wet

Watch for loose wet avalanche activity with rising freezing levels and solar radiation. The avalanche danger can rise quickly.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Cornices

Cornices are gigantic and may become weaker with forecast sun.

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

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 6

Wind Slabs

Recently formed windslabs have likely gained significant strength; however, human triggering may be possible on unsupported terrain at higher elevations.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 22nd, 2013 2:00PM