Avalanche Forecast

Issued: Mar 7th, 2015 7:11AM

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

rbuhler, Avalanche Canada

Kootenay Boundary.

Warm air temperatures with strong afternoon sun may destabilize the upper snowpack on south-facing slopes. Use extra caution on sun exposed slopes during the afternoon.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Warm and sunny is the theme for the next 3 days. On Sunday, mainly sunny conditions are expected with freezing levels reaching around 2300m. Alpine winds are expected to be moderate from the NW. On Monday, full sun is expected with freezing levels reaching upwards of 2500m. Alpine winds are again expected to be moderate from the NW. Conditions are currently forecast to be the same on Tuesday morning with increasing cloudiness during the afternoon. It currently looks like the region can expect snowfall on Wednesday.

Avalanche Summary

On Tuesday and Wednesday there were reports of small wind slabs being triggered by skiers and explosives. On Friday, natural sun-triggered sluffing was reported from steep sun-exposed slopes. As it warms and the amount of sun increases on Sunday, it may become easier to trigger the thin old pockets of wind slabs. During the afternoon it may be possible to trigger sluffing from steep sun-exposed slopes.

Snowpack Summary

Shady and sheltered slopes have 5-15 cm of snow from earlier in the week. Ongoing winds have redistributed this new snow in wind-exposed terrain resulting in a highly variable snow surface and the formation of thin wind slabs in leeward features. Steep sun-exposed slopes have a thin new sun crust on the surface. The most prominent feature in the snowpack is the thick late-Feb crust, down 5-30 cm. This crust is supportive all the way to ridge crest and is effectively "capping" the snowpack, keeping riders from stressing any deeper weak layers. There are still weak layers below this crust that we'll continue to monitor, but for now these layers are dormant. We would likely need significant warming and/or heavy loading to re-activate them.

Problems

Wind Slabs

Ongoing moderate winds from the N through W directions have created pockets of thin wind slabs in leeward terrain features. Afternoon sun and warming may increase the sensitivity of triggering these wind slabs.

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.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Warming temperatures and solar radiation may cause sluffing on steep sun exposed slopes in the afternoon.

Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. >Avoid steep sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 8th, 2015 3:00PM