Avalanche Forecast

Issued: Apr 7th, 2016 8:20AM

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

rbuhler, Avalanche Canada

Sea To Sky.

Extremely warm conditions with strong sun will drive the Avalanche Danger. Be alert to conditions that change throughout the day, and watch your overhead hazard. Large avalanches may run farther than expected.

Summary

Confidence

Moderate

Weather Forecast

A ridge of high pressure will remain the dominant feature for the weekend. Sunny conditions are expected for Friday with moderate southwest winds in the alpine and afternoon freezing levels around 3200m. Mainly sunny conditions are expected for Saturday and Sunday with light alpine winds and afternoon freezing levels around 3000m.

Avalanche Summary

On Wednesday, natural loose wet avalanches up to size 1.5 were reported. Skiers and explosives were triggering wind slabs up to size 1.5 in leeward features and on steep rolls. Small natural cornice falls were reported in the afternoon. With warm and sunny conditions continuing, spring avalanche problems are expected to be the primary concerns. Loose wet avalanches and large cornice falls are expected throughout the forecast period. Lingering wind slabs may also still be a problem on high elevation north aspects.

Snowpack Summary

20-40cm of recent snowfall overlies a mix of old surfaces that formed as a result of last week's big warm-up. The old buried surface includes hard crusts on high elevation solar aspects, settled dry snow in high north-facing alpine terrain, and moist snow everywhere else. The recent snow has been shifted by strong southerly winds into fresh wind slabs in wind-exposed terrain. With forecast solar radiation and warm temperatures, most surfaces will transition to a daily melt-freeze cycle, while recently formed wind slabs will linger on high north-facing slopes. Below the new snow, the snowpack is generally strong and well-settled. Cornices are huge and will become weak with warming and solar radiation.

Problems

Loose Wet

Loose wet sluffing is likely on sun exposed slopes during the heat of the afternoon. Very warm conditions may increase the size and run length of natural sluffing.

Be cautious of wet sluffing in steep terrain. >Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Cornices

Large cornices may become weak with afternoon warming and sun exposure. They can be destructive by themselves, and may also become the trigger for a slab avalanche on the slope below.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

Wind Slabs

Recently formed wind slabs are expected to settle and gain strength with the warm conditions but for the short term I'd remain extra cautious of steep, wind-loaded pockets in the high alpine.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 8th, 2016 2:00PM