Avalanche Forecast

Issued: Feb 16th, 2014 3:00PM

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

Alberta Parks matt.mueller, Alberta Parks

Today was another day of touchy conditions. The strong winds have amplified the windslab problem as shown by the remote triggering witnessed today (see the avalanche observations section). Tread carefully and keep the objectives conservative.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

High winds and flurries are the theme for tomorrow. Snow amounts are limited, but the winds are expected to keep hauling out of the west. Today we found that ridge top winds and valley bottom winds were variable in direction. The same can be expected for tomorrow. As for the temps, no significant change there. A daytime high of -9.

Avalanche Summary

More natural activity was seen today. We suspect most of it happened last night as the winds picked up. The noted activity was alpine and treeline in elevation, north to northeast in aspect and moderate in slope angle. Of note today was a large avalanche remote triggered by forecasters. From 30m away we remoted the opposite side of the ridge on the western end of Tryste Chutes. The avalanche cleaned out three separate gullies and almost crossed the lake. Sz 2.5

Snowpack Summary

Not much new snow overnight. Nearly 10cm's fell at Burstall Pass. The news of the day (and days to come) was the wind. The high winds were also variable in direction. What we're left with is a widespread windslab problem in the alpine. On some aspects the snow has been pressed into a cohesive layer, and other aspects the snow has been blown into a firm windslab. The contributing factor with the new avalanche problem is the facet/surface hoar/sun crust interface layer. On today's snow study trip we visited the Superslope area and had all possible combinations of these snow types as an interface layer. No combinations were bonding well with the new slabs. This bad combination is widespread at alpine and open areas at upper treeline elevations. Below treeline still had well preserved soft snow.

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Thin rocky areas are still the likely trigger point. There has been no activity seen on this layer, but the potential is still there. Stepping down may become a concern as the wind slab avalanches grow in size.
Carefully evaluate and use caution around thin snowpack areas.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Wind Slabs

An icon showing Wind Slabs
These slabs are more of a problem as the winds pick up and become more sustained. The propagations have been larger today than previous days, and sensitivity is going up as well. Avoid any windloaded areas at treeline and alpine.
Avoid freshly wind loaded features.>Avoid areas with overhead hazard.>Avoid cross loaded features.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 4

Valid until: Feb 17th, 2014 2:00PM

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