Turnagain Pass

It looks to be one of those dazzling sunny days in the backcountry. Spring is arriving. Temperatures should be warm and the winds calm. The return of the sun is not only catching some of us searching for our sunglasses and sun screen but impacting our southerly aspects as well. There already exists a variable sun crust that is mainly confined to slopes 35 degrees and steeper (steep enough to catch more of the sun’s rays). However, much of our snow, especially in the Turnagain Pass and Summit areas, has yet to see significant solar effects. If the clouds hold back, today could be the day.

With the expected warm up cornice falls will be our primary concern. These have the potential to be very large and break either on their own or with the added weight of a person. There were many of these monsters overhanging yesterday. It cannot be stressed enough to steer well clear of these both on ridgelines as well as underneath them. I was able to get a closer look at the Magnum cornice fall from Saturday, some photos and details HERE.

Wet loose avalanches will be a concern today as the sun heats up the surface snow. Watching for roller balls, either triggered by you, your sled or occurring naturally under rocks or trees, will be a sign to move to a more shaded aspect. It is that time of year where aspect is key. East slopes will warm first, then south, then west. Planning your route with this in mind and watching what is going on above you will be good practices as we enter into March and April.

Currently, surface conditions exist of mostly soft settled powder with a bit of wind effect and crusts at the upper elevations. A sun crust from Saturday sits just under the surface on southerly aspects but should become softened today.

Additional Concerns:

Wind Slab:
Upper elevations that have seen a bit of wind in the past couple days should be suspect for lingering slabs. These are likely to be hard to trigger and around a foot deep. Having a good exit route planned if one does pop out will be a good idea.

Persistent Slab:
Magnum’s large cornice fall two days ago shed some light on how our buried weak layers and crusts are behaving in the central Turnagain zone. The fact that the cornice was not able to induce a larger slide was very encouraging. However, as we have been mentioning, regions outside Turnagain are more suspect. These include Girdwood Valley, Placer Valley and Grandview (below 3,000’) where a facet/crust combo exists. Additionally, the Summit Lake area harbors weak snow near the ground as well as mid-pack facet/crust combinations. These are outlier issues but good to keep in mind. Safe travel practices, including limiting exposure time in avalanche paths and runnout zones, is a good way maximize a safe day in the backcountry.