Avalanche Forecast

Issued: Apr 8th, 2016 3:00PM

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

rbuhler, Avalanche Canada

Sea To Sky.

Spring conditions typically means the hazard is highest during the heat of the afternoon. Cornices and loose wet sluffing are spring problems which can be expected on Saturday. Wind slabs may also still be lingering in high elevation leeward terrain.

Summary

Weather Forecast

The warm ridge of high pressure persists through the weekend. Saturday and Sunday are expected to be sunny with light alpine winds and afternoon freezing levels around 3000m. Unsettled conditions are expected for Monday with a mix of sun and cloud, and the possibility of light scattered flurries. Moderate southwest winds are expected in the alpine and freezing levels are expected to drop to around 2200m.

Avalanche Summary

On Thursday, a natural cornice fall triggered a size 2 slab on the slope below. A few natural size 2 storm slab avalanches were also reported on high northern aspects. Glide avalanches were reported on steep north facing convexities at treeline. 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. Wet slabs may be possible on steep south facing slopes while the temperatures remain high and overnight recovery is poor. Lingering wind slabs may also still be a problem on high elevation north aspects.

Snowpack Summary

Little to no overnight recovery was reported on Friday morning leaving a moist or wet snow surface on all aspects and elevations. The early-April crust layer is typically down 10-20cm and is reported to be breaking down due to the warm conditions. Prior to the warming, the recent storm snow had been shifted by strong southerly winds into wind slabs in wind-exposed terrain. These wind slabs may still be lingering in high north facing terrain. The mid and lower snowpack are 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, and wet slabs could also be possible.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - 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.

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

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.

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

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 9th, 2016 2:00PM