Avalanche Forecast

Issued: Apr 5th, 2015 9:12AM

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

Avalanche Canada rbuhler, Avalanche Canada

Snowpack and avalanche observations are becoming scarce. If you've been in the backcountry, please tell us what you've seen here on the Mountain Information Network.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

A system to the south of the border will bring precipitation to the region Sunday overnight and Monday. Models are currently showing 5-10mm of precipitation and eastern upslope areas can expect to see the most accumulation. Alpine winds are forecast to be moderate-strong from the SE to E and freezing levels are expected to reach around 1500m on Monday afternoon. On Tuesday, a ridge of high pressure moves over the interior and becomes the dominant feature for the rest of the week. A mix of sun and cloud is expected for Tuesday with light alpine winds and freezing levels reaching around 2000m. On Wednesday, mainly sunny conditions are expected with light alpine winds and freezing levels reaching around 2200m.

Avalanche Summary

Observations are becoming very limited as we enter spring. If you're out in the mountains, please consider posting your observations to our webpage. On Thursday, some loose sluffing was reported from steep terrain. On Saturday in the Lizard region, widespread sluffing was reported from steep terrain features and ski cutting produced soft slabs in wind loaded features. On Monday, it may be possible to trigger new wind slabs in the alpine and exposed areas at treeline. Reverse loading may occur and wind slabs should be expected on all aspects. Cornices may become touchy during the afternoon.

Snowpack Summary

10-15cm of recent snow overlies a widespread and supportive melt-freeze crust. Ongoing moderate-strong winds have redistributed the surface snow resulting in wind slab formation in the alpine and exposed areas at treeline. The winds on Monday are forecast to be from an easterly direction so reverse wind loading can be expected and wind slabs may exist on a variety of aspects. 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. Large cornices exist in the alpine and may become weak with daytime warming.

Problems

Wind Slabs

An icon showing Wind Slabs
New snowfall with moderate-strong winds will form new wind slabs in exposed higher elevation terrain. Watch for triggering in the lee of ridge crests and in gullies.
Travel on ridgetops to avoid wind slabs on slopes below, but be careful with cornices!>Be careful with wind loaded pockets, especially near ridge crests and roll-overs.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices
Large cornices exist at ridge top, and may fail under the weight of a rider. As spring conditions evolve, remember that destructive cornice falls become more likely during periods of warming and solar radiation.
Give cornices a wide berth when traveling on or below ridges. Remember that cornices become weak with daytime heating.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Valid until: Apr 6th, 2015 2:00PM

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