Turnagain Pass

Spring has arrived and so has the sunshine. Yesterday was the first warm sunny Saturday of the year. We had reports of relatively small wet loose avalanches on Southerly aspects and one small dry slab on a Northerly aspect (pictured below). 

Triggering a dry slab avalanche remains a concern on shady aspects. These Northerly slopes have between 8″ to 2′ of soft settled powder from last week’s snowfall. This snow fell on a variable old surface sporting everything from hard snow, facets and crusts. Bonding between the new and old snow was initially poor, but has improved over the past couple days. That said, we are still finding facets in areas under the storm snow and finding and triggering a slab avalanche remains possible. One of these was found yesterday on Tincan mentioned above. Getting your shovel out and quick hand pits are ways to help assess if the storm snow is sticking or not where you happen to be. Obvious signs on instability such as shooting cracks and whumpfing may not be present and these pockets could release further down the slope. As always, practice safe travel protocol, expose one person at a time, have escape routes planned and watch your partners. 
 

Deep Persistent Slabs:  Buried in the middle and toward the bottom of the snowpack are old weak layers of facets and buried surface hoar. These layers formed in January and though they have not been responsible for avalanche activity for over a month or more, the springtime warm up can re-activate old layers. Although very unlikely an avalanche will release in these, it’s good to remember our snowpack has a poor structure. Most concerning areas are those with a thin snow cover such as the Girdwood Valley and the South end of Turnagain Pass and Summit Lake.

 Small slab avalanche triggered remotely on Tincan’s Notherly aspect.

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Wet avalanche activity will again be a concern later in the day on sunlit aspects. Several wet loose avalanches were seen yesterday both natural and human triggered. All these we know of were generally small and easily avoided. Today will likely be a similar scenario. Temperatures are warm this morning at the higher elevations and even with clouds expected later today, the surface crusts are likely to soften. Once the sun crust melts and the snow becomes wet and ‘punchy’ to your boot, it’s time to head to more shaded slopes. Even a small wet snow avalanche can push you around somewhere you don’t want to go.

Wet Slabs: We have not seen any confirmed wet slab avalanche activity yet, but this could be just around the corner. There was a natural slab avalanche on a Westerly aspect in Portage Valley noted yesterday. We don’t have quite enough details, but this could be a sign wet slabs may begin to occur if warm days continue. 

 Wet loose avalanches on Pete’s South, on the Southerly end of Turnagain Pass. 

Slab avalanche seen yesterday in Portage Valley 

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