Avalanche Forecast

Issued: Apr 4th, 2016 8:59AM

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

jlammers, Avalanche Canada

Sea To Sky.

Forecast snowfall amounts for Tuesday are highly uncertain. Pay close attention to how much snow falls in your area, and choose terrain accordingly.

Summary

Confidence

Low - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

On Tuesday expect 5-15cm of new snow. A dry ridge should ensure mainly sunny skies for Wednesday and Thursday. Ridgetop winds should be extreme from the southwest on Tuesday, becoming light on Wednesday and Thursday. Freezing levels should sit at about 1300m on Tuesday and then climb to about 3300m for Wednesday and Thursday.

Avalanche Summary

On Sunday we received reports of heat-induced natural loose wet and cornice avalanches to size 1.5. New wind slab activity is expected in response to new wind and snow on Tuesday.

Snowpack Summary

On Sunday night 3-24cm of new snow fell with the highest accumulations in the southwest of the region. The new snow was shifted by strong southerly winds into fresh wind slabs in wind-exposed terrain. Due to the temperature trend in the storm (warm to cold), the new snow likely developed a reasonable bond to older surfaces which include a mix of hard crusts on high elevation solar aspects, settled dry snow in north-facing alpine terrain, and moist snow everywhere else. Below the new snow, the snowpack is generally strong and well-settled. Cornices are huge and will become weak with future warming and solar radiation.

Problems

Wind Slabs

Forecast snowfall amounts are highly variable for Tuesday, although some areas may get up to 15cm of new snow. Strong to extreme southwest winds will shift the new snow into fresh wind slabs at treeline and in the alpine.

Be cautious as you transition into wind affected terrain.>Travel on ridgetops to avoid wind slabs on slopes below.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

New snow and wind will encourage ongoing cornice growth, and fresh cornice tabs will be weak. If the sun makes an appearance, larger more destructive cornice falls will be possible.

Cornices become weak with daytime heating, so travel early on exposed slopes. >Give cornices a wide berth when traveling on or below ridges. >

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 5

Valid until: Apr 5th, 2016 2:00PM