Avalanche Forecast

Issued: Mar 12th, 2015 8:31AM

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

pgoddard, Avalanche Canada

South Rockies.

Friday is expected to be warm. Avoid exposing yourself to large, sun-baked terrain. Check out the conditions video at http://bit.ly/1EAQd9O

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Friday

Weather Forecast

It’s expected to be dry and very warm (freezing level 3000 m) on Friday. Around 5-10 mm precipitation is expected on Saturday, followed by a further 10 mm or more on Sunday. The freezing level during the precip is around 2200 m, falling to around 1500 m on Sunday, although there is a fair bit of uncertainty about what type of precip we will receive (rain or snow). Winds are moderate to strong from the SW.

Avalanche Summary

On Tuesday, our field team members in the north Elk Valley experienced several whumpfs on south facing treed terrain at 2200 m. They also experienced a whumpf of a hard slab near ridge top at 2450 m and saw a deep slab release on a sunny aspect that probably occurred some time in the last week. Recent loose wet avalanches up to size 1.5 appeared to have been triggered by solar warming. On Sunday, a skier-triggered slab released on a weak layer near the ground in Kananaskis Country. As temperatures remain very warm for the next few days, it might be time for a mentality shift. Treat the snowpack with more caution than in recent weeks. Large avalanches are becoming more likely again.

Snowpack Summary

Any available snow may be shifted by SW winds into wind slabs at high elevations. Lower down the mountain, the snowpack has become warm and weak. The most prominent snowpack feature is a thick supportive crust 10-30cm below the surface. It extends up to around 2200m elevation. This crust has begun to break down in response to warm temperatures, and may not be providing the capping support it once was. Persistent weak layers still react in snowpack tests and could wake up with continued warming.

Problems

Loose Wet

A hot sunny day may spark a cycle of loose wet or wet slab avalanches. Time your travel on Friday to take advantage of cooler parts of the day.

Avoid steep or committing slopes if the snow is moist or wet.>Cornices become weak with heating, so avoid exposing yourself to them.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

We have concerns about this problem "waking up" with warm temperatures. A crust that previously isolated deep weaknesses has broken down with warming. Recent whumpfing indicates unstable snow.

Avoid large slopes during times of warm temperatures.>Be aware of thin areas and rock outcroppings where you are more likely to trigger a deep slab.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Wind Slabs

Caution near ridge tops for wind slabs that could be triggered with the weight of a person.

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

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Mar 13th, 2015 2:00PM