Avalanche Forecast

Issued: Apr 4th, 2015 8:42AM

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

rbuhler, Avalanche Canada

Kootenay Boundary.

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 cool unstable airmass will linger over the interior on Sunday. The region can expect a mix of sun and cloud with localized convective flurries. Alpine winds are expected to be moderate from the NE to E and freezing levels are expected to reach around 1700m in the afternoon. A weak system south of the border should bring light precipitation to region Sunday overnight and Monday. Models are currently showing 5-10mm. Alpine winds are forecast to be moderate from the E and freezing levels are expected to reach around 1600m. A ridge of high pressure builds on Tuesday and should bring dry and mainly clear conditions for the rest of the week. Freezing levels are expected to reach around 2000m on Tuesday and progressively climb higher later in the week.

Avalanche Summary

Observations are becoming more limited as we enter spring. If you're out in the mountains, please consider posting your observations to our webpage. On Friday, some loose dry sluffing was reported from steep terrain. On Wednesday, ski cutting produced numerous size 1 wind slabs. On Sunday, it may be possible to trigger new wind slabs in the alpine and exposed areas at treeline. Cornices may be touchy, especially during the heat of the day. Extra caution should be given to all steep south facing slopes when the sun is out during the heat of the afternoon.

Snowpack Summary

10-20cm of new snow overlies a thick supportive melt-freeze crust. At higher elevations these accumulations have been blown around by variable winds and new wind slabs may exist on a variety of aspects. The mid-March crust/facet complex is buried around 50cm below the surface. This layer is generally considered dormant while the cooler temperatures prevail. The mid and lower snowpack are strong and well settled.

Problems

Wind Slabs

Light snowfall and moderate winds have formed new wind slabs in exposed terrain at higher elevations. Watch for triggering in the lee of ridge crests and in gullies.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.>Travel on ridgetops to avoid wind slabs on slopes below, but be careful with cornices!>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Sluffing can be expected from steep sun-exposed slopes during the heat of the afternoon.

Be cautious of sluffing in steep terrain.>Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. >

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Large cornices exist at ridgetop and may fail under the weight of a human-trigger. 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 5th, 2015 2:00PM