Avalanche Forecast

Issued: Apr 11th, 2015 3:00PM

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

Peter, Avalanche Canada

South Rockies.

Spring flurries and wind may combine to build fresh wind slabs in lee features. Also, loose wet slides are possible whenever the sun pokes out.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Sunday: A mix of sun and cloud with a chance of showers. The freezing level is around 1500-1700 m and ridge winds are moderate from the West. Monday: Sun and cloud to start, with increasing cloud and a chance of flurries late or overnight. The freezing level bumps up to 2000-2200 m. Winds are moderate gusting strong from the S-SW. Tuesday: Cloudy with flurries. The freezing level lowers to 1600 m and wind remain moderate from the W-SW.

Avalanche Summary

One size 2 loose wet slide was reported in the Lizard Range on Friday. Observations are becoming more limited as we enter into spring. If you're out in the mountains, please consider posting your observations to our webpage using the Mountain Information Network.

Snowpack Summary

Up to 20cm of recent snow overlies a widespread and supportive melt-freeze crust on higher shady slopes, while melt-freeze conditions are more likely on sun-exposed and lower elevation slopes. In some areas, winds may have redistributed the surface snow resulting in wind slab formation in the alpine and exposed areas at treeline. Large cornices exist in the alpine and may become weak with daytime warming. The mid-March rain crust is down 35 to 70cm and has shown a good bond with snow above. Old persistent weak layers are still intact in the mid and lower snowpack and there may be potential for these layers to wake up with a big cornice fall, sustained warming and/or a significant rain event.

Problems

Wind Slabs

New snow may get blown into fresh wind slabs on the immediate lee of ridge lines and other terrain breaks. Where unaffected by wind, loose snow sitting on a crust could sluff easily in steep terrain.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

Large cornices at ridgetop may fail under the weight of a person. Cornices may grow further with anticipated new snow and wind, and will remain unstable, particularly during periods of warming.

Give cornices a wide berth when traveling on or below ridges. Remember that cornices become weak with daytime heating.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Apr 12th, 2015 2:00PM