Avalanche Forecast

Issued: Feb 10th, 2017 3:30PM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs, Wind Slabs and Deep Persistent Slabs.

Alberta Parks matt.mueller, Alberta Parks

Avoid any exposure to avalanche terrain. A SPAW is also in effect. Please read it thoroughly and share among other backcountry users.

Summary

Confidence

High -

Weather Forecast

Tonight will see the winds continue with flurries bringing another 4cm. Tomorrow we're expecting another unsettled weather day with a little bit of everything The winds will continue to beĀ  40-50km/hr range. The temps will fall overnight. Tomorrow's high will be -14.

Avalanche Summary

-A sz3 was reported on Mt. Warspite. It had a wide propagation and traveled full path. -A sz2.5 was noted on a sub peak of Mt. Chester. West aspect, alpine start zone. It had a very unusual/erratic propagation-The rundle range had a widespread cycle at treeline and below and some alpine activity. Lots of small pockets that pulled out. High consequence avalanches despite being small-Mt Cascade (Cascade Falls & Urs Hole) went sz3

Snowpack Summary

Its hard to paint a widespread picture of the snowpack right now. At treeline, there is 50-60cm of settled storm snow. Generally this new snow is still considered soft (4f), however in more exposed areas it is noticeably denser(1f). This change is from either wind transport, wind pressing or settlement. The real story is what its sitting on. At treeline and below, it is sitting on the facets from earlier this year. During our field trip today (Superslope area) there was widespread whumphing and cracking. In more open, wind exposed terrain, the new snow is sitting on a hard windslab that was buried on Feb 4th. In these areas the snowpack feels better under foot, but under the hardslab is a well developed facet layer that will create large avalanches if it fails. The alpine is currently being hammered by the wind and we are expecting start zones to be filling up with wind blown snow. The forecasting team's gut feeling today is that any open terrain greater than 20 degrees should be avoided.

Problems

Storm Slabs

An icon showing Storm Slabs
These slabs are formed from wind transport, warm temps or wind pressing. Widespread whumphing and cracking in all terrain. Even a small avalanche on this layer will have consequences due to the amount of snow.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 3

Wind Slabs

An icon showing Wind Slabs
Expect to find this in exposed areas. The slab appears to be helping distribute the new snow load over the weaker layers below. Use your probe to find the layer. Don't be fooled by a seemingly settled snowpack.
If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Many avalanches have stepped to this layer. Very large avalanches can be expected if this layer is involved.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Feb 11th, 2017 2:00PM