Turnagain Pass Avalanche Forecast

We had a few second hand reports of a skier triggered slab avalanche in the Tincan Proper area yesterday. The slide was triggered by the 2nd skier on the slope, who took a similar line to the first skier. It broke 3-6′ deep, a little bit below the ridge and in steep 45 degree terrain (seen in the photo below that was taken from the Sunburst ridge). The skier was able to escape being caught. It appears this avalanche could have broken in weak snow near the ground, making it more complicated than just a wind slab. We hope to gather more information today.

Skier triggered slab avalanche on the western rib of Tincan Proper. 12.3.20. Photo: Thomas Bailly

Although much of the snowpack is gaining strength with the cool temperatures after Wednesday’s warm and wet storm, there are still areas that are concerning for triggering an avalanche. These are steep wind loaded slopes and gullies in more complex terrain. Even more concerning are those places that are unsupported, meaning slopes that rollover into steeper terrain or cliff features. The avalanche that was triggered yesterday is an example of this type of terrain.

If you’re headed out today, at elevations above the ‘dust on crust’, be suspect of these steep wind loaded features, and cornices for that matter. As usual, watch for cracking and collapsing in the snow around you. However, not many signs of instability are likely to be present. In fact, it may not be the wind slab itself that is unstable anymore, but the weak older snow below it, creating for a bit of a tricky situation discussed below.

Unfortunately, we can’t quite forget about that old weak snow near the ground and the chance a person could trigger a large avalanche. The pummeling of the recent storms helped us out a lot, but there are still areas to be suspect of. These are not only wind loaded steep slopes, but thin areas in the snowpack and especially shallow snowpack zones, such as the south end of Turnagain Pass through Summit Lake. In these shallower snowpacks, it’s technically easier to trigger an avalanche breaking near the ground because our weight can better impact the weak layer.

Things to keep in mind:

• The snowpack can feel ‘stable’ and no signs of instability may be present before a deep slab releases.
• The likelihood of triggering a large slab increases if you find shallower spots in the snowpack and near rocky areas.
• Slopes may already have tracks on them and then still release.
• These slabs can be triggered remotely, from the bottom, top or side.

This is a good time for us to remember our safe travel practices. One person on a slope at a time, really watch our partners, have escape zones planed along with safe zones to watch from.