Turnagain Pass

A ‘Normal Caution’ avalanche regime exists in the backcountry surrounding Turnagain Pass and triggering an avalanche is unlikely. Temperatures have dropped to near 10°F along the ridgetops and near 20°F in parking lots overnight. This has frozen any remaining wet or moist snow and a stout crust can be expected at all elevations and aspects. Observers have reported that even on high elevation shady north aspects a melt-freeze crust exists; this was formed from the warm cloudy weather last Wednesday.

Glide avalanches:  Despite the low danger, glide avalanches could still pose a problem. Although the temperatures are cool, this type of avalanche could release at anytime and is not associated with a human trigger. Watch for glide cracks and limit any expose under them. A few glide cracks are beginning to open and several released on Thursday. Some of these were on Raggedtop in Girdwood Valley, below Tincan Proper and in Peterson drainage. It appears one glide crack may be opening up on Seattle Ridge to the left of the up-track.

Several glide avalanches popped below Tincan Proper on Thursday, 3.26.20. Note the one on the left side of the photo with debris that ran down to the valley bottom that almost covered ski tracks.

Avalanche Outlook for Sunday through next week:
Timing is everything during the spring. Beginning on Sunday, we head into a clear sky period with cold nights and warm(ish) days. Solar warming on southerly slopes, combined with light winds, may be enough to soften and melt surface crusts. Once the crusts melt and the cohesion is lost, avalanche danger will rise. Both wet loose and wet slab avalanches will become possible and this will be the key for avoiding avalanche issues during the coming week.

Wet loose avalanches:  Watch for daytime warming to soften surface crusts on steep southerly slopes. Once the snow is punchy and becoms saturated, wet sluffs will be easy to trigger. These can run much further than expected on large slopes and entrain a significant amount of snow.

Wet slab avalanches:  Similar to wet loose avalanches, once the surface crusts melt, wet slab avalanches will become possible. These could also have a dry slab character in the higher terrain where dry snow exists under the surface crust. Areas most suspect are those with a shallow snowpack harboring weak faceted snow in the mid and base of the pack, such as on the south end of Turnagain Pass and in the Summit Lake area.

Cornice falls:  Warming during the heat of the day can weaken cornices and make them more tender to trigger. Something to keep in mind for the remainder of the snow season.

Lingering wind slabs:  There still could be some lingering wind slabs in the high elevation rocky terrain that are not yet welded into place. Daytime warming can cause these to become more sensitive and as always, be wary of wind deposited stiff snow over weaker snow.